The doctrine of sola fide or "by faith alone" asserts God's pardon for guilty sinners is granted to and received through faith, conceived as excluding all "works," alone. All mankind, it is asserted, is fallen and sinful, under the curse of God, and incapable of saving itself from God's wrath and curse. But God, on the basis of the life, death, and resurrection of his Son, Jesus Christ alone (solus Christus), grants sinners judicial pardon, or justification, which is received solely through faith. Faith is seen as passive, merely receiving Christ and all his benefits, among which benefits are the active and passive righteousness of Jesus Christ. Christ's righteousness, according to the followers of "sola fide," is imputed (or attributed) by God to the believing sinner (as opposed to infused or imparted), so that the divine verdict and pardon of the believing sinner is based not upon anything in the sinner, nor even faith itself, but upon Jesus Christ and his righteousness alone, which are received through faith alone. Justification is by faith alone and is distinguished from the other graces of salvation. See the Protestant ordo salutis for more detail on the doctrine of salvation considered more broadly than justification by faith alone.
Historic Protestantism (both Lutheran and Reformed) has held to sola-fide justification in opposition to Roman Catholicism especially, but also in opposition to significant aspects of Eastern Orthodoxy. Protestants exclude all human works (except the works of Jesus Christ, which form the basis of justification) from the legal verdict / pardon of justification. In the General Council of Trent the Catholic Church stated in canon XIV on justification that "If any one saith, that man is truly absolved from his sins and justified, because that he assuredly believed himself absolved and justified; or, that no one is truly justified but he who believes himself justified; and that, by this faith alone, absolution and justification are effected; let him be anathema (excommunicated)." Thus, "faith alone" is foundational to Protestantism, and distinguishes it from other Christian denominations. According to Martin Luther, justification by faith alone is the article on which the church stands or falls.
Christian theologies answer questions about the nature, function, and meaning of justification quite differently. These issues include: Is justification an event occurring instantaneously or is it as an ongoing process? Is justification effected by divine action alone (monergism), by divine and human action together (synergism), or by human action? Is justification permanent or can it be lost? What is the relationship of justification to sanctification, the process whereby sinners become righteous and are enabled by the Holy Spirit to live lives pleasing to God?
From 1510 to 1520, Luther lectured on the Psalms, the books of Hebrews, Romans, and Galatians. As he studied these portions of the Bible, he came to view the use of terms such as penance and righteousness by the Roman Catholic Church in new ways. (See Romans 4:1-5, Galatians 3:1-7, and Genesis 15:6.) He became convinced that the church was corrupt in its ways and had lost sight of what he saw as several of the central truths of Christianity, the most important of which, for Luther, was the doctrine of justification—God's act of declaring a sinner righteous—by faith alone through God's grace. He began to teach that salvation or redemption is a gift of God's grace, attainable only through faith in Jesus.
"This one and firm rock, which we call the doctrine of justification," insisted Martin Luther, "is the chief article of the whole Christian doctrine, which comprehends the understanding of all godliness." He also called this doctrine the articulus stantis et cadentis ecclesiae ("article of the standing and falling of the church"): "…if this article stands, the Church stands; if it falls, the Church falls." Lutherans follow Luther in this when they call this doctrine "the material principle" of theology in relation to the Bible, which is "the formal principle." They believe justification by grace alone through faith alone in Christ's righteousness alone is the gospel, the core of the Christian faith around which all other Christian doctrines are centered and based.
Luther came to understand justification as entirely the work of God. When God's righteousness is mentioned in the gospel, it is God's action of declaring righteous the unrighteous sinner who has faith in Jesus Christ. The righteousness by which the person is justified (declared righteous) is not his own (theologically, proper righteousness) but that of another, Christ (alien righteousness). "That is why faith alone makes someone just and fulfills the law," said Luther. "Faith is that which brings the Holy Spirit through the merits of Christ." Thus faith, for Luther, is a gift from God, and "...a living, bold trust in God's grace, so certain of God's favor that it would risk death a thousand times trusting in it." This faith grasps Christ's righteousness and appropriates it for the believer. He explained his concept of "justification" in the Smalcald Articles:
The first and chief article is this: Jesus Christ, our God and Lord, died for our sins and was raised again for our justification (Romans 3:24-25). He alone is the Lamb of God who takes away the sins of the world (John 1:29), and God has laid on Him the iniquity of us all (Isaiah 53:6). All have sinned and are justified freely, without their own works and merits, by His grace, through the redemption that is in Christ Jesus, in His blood (Romans 3:23-25). This is necessary to believe. This cannot be otherwise acquired or grasped by any work, law or merit. Therefore, it is clear and certain that this faith alone justifies us ... Nothing of this article can be yielded or surrendered, even though heaven and earth and everything else falls (Mark 13:31).
Traditionally, Lutherans have taught forensic (or legal) justification, a divine verdict of acquittal pronounced on the believing sinner. God declares the sinner to be "not guilty" because Christ has taken his place, living a perfect life according to God's law and suffering for his sins. For Lutherans justification is in no way dependent upon the thoughts, words, and deeds of those justified through faith alone in Christ. The new obedience that the justified sinner renders to God through sanctification follows justification as a consequence, but is not part of justification.
Lutherans believe that individuals receive this gift of salvation through faith alone. Saving faith is the knowledge of, acceptance of, and trust in the promise of the Gospel. Even faith itself is seen as a gift of God, created in the hearts of Christians by the work of the Holy Spirit through the Word and Baptism. Faith is seen as an instrument that receives the gift of salvation, not something that causes salvation. Thus, Lutherans reject the "decision theology" which is common among modern evangelicals.
For Lutherans, justification provides the power by which Christians can grow in holiness. Such improvement comes about in the believer only after he has become a new creation in Christ through Holy Baptism. This improvement is not completed in this life: Christians are always "saint and sinner at the same time" (simul iustus et peccator)—saints because they are holy in God's eyes, for Christ's sake, and do works that please him; sinners because they continue to sin until death.
Origin of the term
1861 painting of Luther discovering the Sola fide doctrine at Erfurt
Martin Luther elevated sola fide to the principal cause of the Protestant Reformation, the rallying cry of the Protestant cause, and the chief distinction between Protestant Christianity and Roman Catholicism. John Calvin, also a proponent of this doctrine, taught that "every one who would obtain the righteousness of Christ must renounce his own." According to Calvin, it is only because the sinner is able to obtain the good standing of the Son of God, through faith in him, and union with him, that sinners have any hope of pardon from, acceptance by, and peace with God.
Protestants base this on the fact that the New Testament contains almost two hundred statements that appear to imply that faith or belief is sufficient for salvation. For example: "Jesus said unto her, I am the resurrection, and the life: he that believe in me, though he were dead, yet shall he live." (John 11:25, emphasis added). And especially Paul's words in Romans, "Therefore we conclude that a man is justified by faith without the deeds of the law." (Romans 3:28) "Now to him that worketh is the reward not reckoned of grace, but of debt. But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness." (Romans 4:4-5)
The place of works
The position that justification is by faith alone has often been charged with promoting antinomianism, in which salvific faith need not be a type that will produce works of obedience to Christ, which is a view most who hold to sola fide reject, invoking many authorities from the past and present in concurrence.
Martin Luther, who opposed antinomianism, is recorded as stating, “Works are necessary for salvation but they do not cause salvation; for faith alone gives life.”
In his Introduction to Romans, Luther stated that saving faith is,
a living, creative, active and powerful thing, this faith. Faith cannot help doing good works constantly. It doesn’t stop to ask if good works ought to be done, but before anyone asks, it already has done them and continues to do them without ceasing. Anyone who does not do good works in this manner is an unbeliever...Thus, it is just as impossible to separate faith and works as it is to separate heat and light from fire! 
“Faith alone justifies but a justified person with faith alone would be a monstrosity which never exists in the kingdom of grace. Faith works itself out through love (Gal. 5:6). And Faith without works is dead (James 2:17-20).”
“It is living faith that justifies and living faith unites to Christ both in the virtue of his death and in the power of his resurrection. No one has entrusted himself to Christ for deliverance from the guilt of sin who has not also entrusted himself to him for deliverance from the power of sin.”
The relationship of faith and good works is one that may be distinguished but never separated...if good works do not follow from our profession of faith, it is a clear indication that we do not possess justifying faith. The Reformed formula is, “We are justified by faith alone but not by a faith that is alone.”
This debate, therefore, is not over the question of whether God renews us and initiates a process of gradual growth in holiness throughout the course of our lives. ‘We are justified by faith alone, but not by a faith that is alone,’ Luther stated, and this recurring affirmation of the new birth and sanctification as necessarily linked to justification leads one to wonder how the caricatures continue to be perpetuated without foundation.
Status of the doctrine
The doctrine proposes that faith in Christ is sufficient for sinners to be accepted by God, to count them among his people, and to equip them with the motive of trust, gratitude, and love toward God from which good works are to be done. Some Christian groups such as Catholics believe that faith is necessary for salvation but not sufficient; that is, they assert that sola fide is an error because, in addition to believing, God also requires obedience and acts of love and charity as a prerequisite for acceptance into his kingdom, and for the reward of eternal life. This is in line with the traditional view of faith as faithfulness [to God] in the Old Testament. See also Christian view of the Old Testament Law.
The precise relationship between faith and good works remains as an area of controversy in some Protestant traditions (see also Law and Gospel). Even at the outset of the Reformation, subtle differences of emphasis appeared. For example, because the Epistle of James emphasizes the importance of good works, Martin Luther sometimes referred to it as the "epistle of straw." Calvin on the other hand, while not intending to differ with Luther, described good works as a consequence or 'fruit' of faith. The Anabaptists tended to make a nominal distinction between faith and obedience. Recent meetings of scholars and clergy have attempted to soften the antithesis between Protestant and Catholic conceptions of the role of faith in salvation, which, if they were successful, would have far reaching implications for the relationship between most Protestants and the Catholic Church. These attempts to form a consensus are not widely accepted among either Protestants or Catholics, so sola fide continues to be a doctrinal distinctive of the Reformation churches, including Lutherans, Reformed, and many Evangelicals. Nevertheless, some statements of the doctrine are interpreted as a denial of the doctrine as understood by other groups.
There is a semantic component to this debate as well, which has gained new attention in the past century. Both Latin and English have two words to describe convictions: one is more intellectual (English belief, Latin verb credo) and one carries implications of "faithfulness" (English faith, Latin fides). But Greek and German have only one (German Glaube, Greek pistis). Some historians have suggested that this semantic issue caused some of the disagreement: Perhaps Luther's supporters may have understood "salvation by faith alone" to mean "salvation by being faithful to Christ," while his opponents understood him to mean "salvation by intellectual belief in Christ." Since there are passages in Luther's works that could be taken to support either of these meanings, both sides were able to quote passages from Luther defending their interpretation of what he meant.
Various Biblical passages have been used to support and oppose the doctrine of sola fide.
Passages used to defend sola fide
John 3:36: "Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him." (English Standard Version)
"And he who believes in (has faith in, clings to, relies on) the Son has (now possesses) eternal life. But whoever disobeys (is unbelieving toward, refuses to trust in, disregards, is not subject to) the Son will never see (experience) life, but [instead] the wrath of God abides on him. [God’s displeasure remains on him; His indignation hangs over him continually.] " (Amplified Version)
"He who believes in the Son has everlasting life; and he who does not believe the Son shall not see life, but the wrath of God abides on him.” (New King James Version)
Genesis 15:6 "And he believed the Lord; and the Lord reckoned it to him as righteousness."
Isaiah 55:1 "Come, all you who are thirsty, come to the waters; and you who have no money, come, buy and eat! Come, buy wine and milk without money and without cost."
Matthew 7:22-23: "Many will say to me in that day, 'Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?' And then will I profess unto them, I never knew you: depart from me, ye that work iniquity."
Luke 5:20: "And when he saw their faith, he said unto them, Man, thy sins are forgiven thee."
Luke 18:10-14: "Two men went up to the temple to pray, one a Pharisee and the other a tax collector. The Pharisee stood up and prayed about himself: 'God, I thank you that I am not like other men—robbers, evildoers, adulterers—or even like this tax collector. I fast twice a week and give a tenth of all I get.' But the tax collector stood at a distance. He would not even look up to heaven, but beat his breast and said, 'God, have mercy on me, a sinner.' I tell you that this man, rather than the other, went home justified before God."
Luke 23:40-43: "But the other criminal rebuked him. 'Don't you fear God,' he said, 'since you are under the same sentence? We are punished justly, for we are getting what our deeds deserve. But this man has done nothing wrong.' Then he said, 'Jesus, remember me when you come into your kingdom.' Jesus answered him, 'I tell you the truth, today you will be with me in paradise.'"
John 3:16: "For God so loved the world, that He gave His only begotten Son, so that whoever believes in Him shall not perish, but have eternal life."
John 3:18: "Whoever believes in him is not condemned, but whoever does not believe stands condemned already because he has not believed in the name of God's one and only Son."
John 6:28-29: "Then they said unto him, 'What shall we do, that we might work the works of God?' Jesus answered and said unto them, 'This is the work of God, that ye believe on him whom he hath sent.'"
John 5:24: "Verily, verily, I say unto you, He that heareth my word, and believeth him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life."
John 6:40: "And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life, and I will raise him up at the last day."
John 6:47: "Verily, verily, I say unto you, He that believeth on me hath everlasting life."
Acts 10:43: "Of Him all the prophets bear witness that through His name everyone who believes in Him receives forgiveness of sins."
Acts 16:31: "Believe on the Lord Jesus Christ, and you shall be saved."
John 14:6: "Jesus saith unto him, I am the way, the truth, and the life: no man cometh to the Father, but by me."
Acts 26:18: "...that they may receive forgiveness of sins and an inheritance among those who are sanctified by faith in me..."
Romans 1:17-18: "Therefore the just shall live by faith. The wrath of God is indeed being revealed from heaven against every impiety and wickedness of those who suppress the truth by their wickedness."
Romans 3:28: "Therefore we conclude that a man is justified by faith without the deeds of the law."
Romans 4:5: "But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness."
Romans 5:1: "Therefore being justified by faith, we have peace with God through our Lord Jesus Christ."
Romans 6:23 "For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord."
Romans 10:9: "That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved."
Romans 11:6: "And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then is it no more grace: otherwise work is no more work."
Romans 14:23: "...for whatsoever is not of faith is sin."
Corinthians 1:21: "For since, in the wisdom of God, the world through wisdom did not know God, it pleased God through the foolishness of the message preached to save those who believe."
Galatians 2:16: "Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified."
Galatians 2:21: "I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain."
Galatians 3:1-3; 9-14; 21-25: "O foolish Galatians, who hath bewitched you, that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you? This only would I learn of you, Receive ye the Spirit by the works of the law, or by hearing of faith? Are you so foolish? having begun in the Spirit, are ye now made perfect by the flesh? ... So then they which be of faith are blessed with faithful Abraham. For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them. But that no man is justified by the law in the sight of God, it is evident: for, The just shall live by faith. And the law is not of faith: but, The man that doeth them shall live in them. Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth on a tree. That the blessing of Abraham might come on the Gentiles through Jesus Christ; so that we might receive the promise of the Spirit through faith.... Is the law then against the promises of God? God forbid: for if there had been a law given which could have given life, verily righteousness should have been by the law. But the Scripture harh concluded all under sin, that the promise by faith of Jesus Christ might be given to them that believe. But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed. Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith. But after that faith is come, we are no longer under a schoolmaster."
Galatians 5:4,5: "Christ is become of no effect unto you, whosoever of you are justified by the law; ye are fallen from grace. For we through the Spirit wait for the hope of righteousness by faith."
Ephesians 1:13-14: "In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise, who is the guarantee of our inheritance until the redemption of the purchased possession, to the praise of His glory."
Ephesians 2:8-10: "For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them."
Philippians 3:9: "And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith."
Galatians 3:8: "The Scripture foresaw that God would justify the Gentiles by faith..."
1 Timothy 1:16: "However, for this reason I obtained mercy, that in me first Jesus Christ might show all long suffering, as a pattern to those who are going to believe on Him for everlasting life."
Titus 3:5: "Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost."
Passages used to argue against sola fide
Psalm 15: A Psalm of David. O LORD, who may abide in Your tent? Who may dwell on Your holy hill? He who walks with integrity, and works righteousness, And speaks truth in his heart. He does not slander with his tongue, Nor does evil to his neighbor, Nor takes up a reproach against his friend; In whose eyes a reprobate is despised, But who honors those who fear the LORD; He swears to his own hurt and does not change; He does not put out his money at interest, Nor does he take a bribe against the innocent. He who does these things will never be shaken. (NASB)
Matthew 5:16: "Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven."
Matthew 7:21 (part of the Sermon on the Mount): "Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven."
Matthew 7:24-27 (part of the Sermon on the Mount): "Therefore everyone who hears these words of mine and puts them into practice is like a wise man who built his house on the rock. The rain came down, the streams rose, and the winds blew and beat against that house; yet it did not fall, because it had its foundation on the rock. But everyone who hears these words of mine and does not put them into practice is like a foolish man who built his house on sand. The rain came down, the streams rose, and the winds blew and beat against that house, and it fell with a great crash."
Matthew 12:36-37: "I tell you, on the day of judgment you will have to give an account for every careless word you utter; For by your words you will be justified, and by your words you will be condemned."
Matthew 16:27: "For the Son of Man is going to come in his Father's glory with his angels, and then he will reward each person according to what he has done."
Matthew 19:16-21: "And behold, one came to him and said, Teacher, what good thing shall I do, that I may have eternal life? And he said unto him, Why askest thou me concerning that which is good? One there is who is good: but if thou wouldest enter into life, keep the commandments. He saith unto him, Which? And Jesus said, Thou shalt not kill, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness, Honor thy father and mother; and, Thou shalt love thy neighbor as thyself. The young man saith unto him, All these things have I observed: what lack I yet? Jesus said unto him, If thou wouldest be perfect, go, sell that which thou hast, and give to the poor, and thou shalt have treasure in heaven: and come, follow me.”
Matthew 24:10-20 (part of the Olivet discourse): "Then many will fall away, and they will betray one another and hate one another. And many false prophets will arise and lead many astray. And because of the increase of lawlessness, the love of many will grow cold. But the one who endures to the end will be saved."
Matthew 25:31-46 (part of The Sheep and the Goats): "When the Son of Man comes in his glory, and all the angels with him, he will sit on his throne in heavenly glory. All the nations will be gathered before him, and he will separate the people one from another as a shepherd separates the sheep from the goats. He will put the sheep on his right and the goats on his left. Then the King will say to those on his right, 'Come, you who are blessed by my Father; take your inheritance, the kingdom prepared for you since the creation of the world. For I was hungry and you gave me something to eat, I was thirsty and you gave me something to drink, I was a stranger and you invited me in, I needed clothes and you clothed me, I was sick and you looked after me, I was in prison and you came to visit me.' Then the righteous will answer him, 'Lord, when did we see you hungry and feed you, or thirsty and give you something to drink? When did we see you a stranger and invite you in, or needing clothes and clothe you? When did we see you sick or in prison and go to visit you?' The King will reply, 'I tell you the truth, whatever you did for one of the least of these brothers of mine, you did for me.' Then he will say to those on his left, 'Depart from me, you who are cursed, into the eternal fire prepared for the devil and his angels. For I was hungry and you gave me nothing to eat, I was thirsty and you gave me nothing to drink, I was a stranger and you did not invite me in, I needed clothes and you did not clothe me, I was sick and in prison and you did not look after me.' They also will answer, 'Lord, when did we see you hungry or thirsty or a stranger or needing clothes or sick or in prison, and did not help you?' He will reply, 'I tell you the truth, whatever you did not do for one of the least of these, you did not do for me.' Then they will go away to eternal punishment, but the righteous to eternal life."
Matthew 28:19-20a (part of the Great Commission): "Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you."
Luke 8:21: "But He answered and said to them, 'My mother and My brothers are these who hear the word of God and do it.' "
Luke 10:25-28: "On one occasion an expert in the law stood up to test Jesus. 'Teacher,' he asked, 'what must I do to inherit eternal life?' 'What is written in the Law?' he replied. 'How do you read it?' He answered: 'Love the Lord your God with all your heart and with all your soul and with all your strength and with all your mind'; and, 'Love your neighbor as yourself.' 'You have answered correctly,' Jesus replied. 'Do this and you will live.'"
John 5:29: "And will come out, those who have done good, to the resurrection of life, and those who have done evil, to the resurrection of condemnation."
Acts 26:20: "First to those in Damascus, then to those in Jerusalem and in all Judea, and to the Gentiles also, I preached that they should repent and turn to God and prove their repentance by their deeds."
Romans 2:6,7; 13: "For he will repay according to each one's deeds. To those who by patiently doing good seek for glory and honor and immortality, he will give eternal life; for it is not those who hear the law who are just in the sight of God; rather, those who observe the law will be justified."
Romans 2:16: "on the day when, according to my gospel, God, through Jesus Christ, will judge the secret thoughts of all."
Galatians 6:7b-9: "A man reaps what he sows. The one who sows to please his sinful nature, from that nature will reap destruction; the one who sows to please the Spirit, from the Spirit will reap eternal life. Let us not become weary in doing good, for at the proper time we will reap a harvest if we do not give up."
1 Corinthians 7: 19: "Circumcision means nothing and uncircumicsion means nothing; what matters is keeping God's commandments."
1 Corinthians 10:12: "Wherefore let him that thinketh he standeth take heed lest he fall."
1 Corinthians 13:2-3: "And if I have prophetic powers, and understand all mysteries and all knowledge, and if I have all faith, so as to remove mountains, but do not have love, I am nothing. If I give away all my possessions, and if I hand over my body so that I may boast, but do not have love, I gain nothing."
1 Corinthians 13:13: "And now faith, hope, and love abide, these three; and the greatest of these is love."
2 Corinthians 5:10: "For we must all appear before the judgement seat of Christ; that every one may receive the things done is his body, according to that he hath done, whether it be good or bad."
Philippians 2:12b-13: "Work out your salvation with fear and trembling, For God is one who, for his good purpose, works in you both to desire and to work."
1 Timothy 4:16: "Attend to yourself and to your teaching; persevere in both tasks, for by doing so you will save both yourself and those who listen to you."
1 Timothy 6:18-19: "That they do good, that they be rich in good works, ready to distribute, willing to communicate; Laying up in store for themselves a good foundation against the time to come, that they may lay hold on eternal life."
Hebrews 10:24: "And let us consider how we may spur one another on toward love and good deeds."
James 1:22: "Do not merely listen to the word, and so deceive yourselves. Do what it says."
James 2 (excerpts): "... What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him? ... Thou believest that there is one God; thou doest well: the devils also believe, and tremble. But wilt thou know, O vain man, that faith without works is dead? Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar? Seest thou how faith wrought with his works, and by works was faith made perfect? ... Ye see then how that by works a man is justified."
James 2:24: "You see that a person is justified by works and not by faith alone."
1 Peter 1:17: "Now if you invoke as Father him who judges impartially according to each one's works, conduct yourselves with reverence during the time of your sojourning."
1 Peter 2:12: "Having your conversation honest among the Gentiles: that, whereas they speak against you as evildoers, they may by your good works, which they shall behold, glorify God in the day of visitation."
1 John 2:3-7: "We know that we have come to know him if we obey his commands. The man who says, 'I know him,' but does not do what he commands is a liar, and the truth is not in him. But if anyone obeys his word, God's love is truly made complete in him. This is how we know we are in him: Whoever claims to live in him must walk as Jesus did. Dear friends, I am not writing you a new command but an old one, which you have had since the beginning. This old command is the message you have heard."
1 John 3:17-18: "If anyone has material possessions and sees a brother or sister in need but has no pity on them, how can the love of God be in that person? Dear children, let us not love with words or speech but with actions and in truth."
Revelation 2:23: "Then all the churches will know that I am he who searches hearts and minds, and I will repay each of you according to your deeds."
Revelation 14:12-13: "Here is a call for the endurance of the saints, those who keep the commandments of God and hold fast to the faith of Jesus. And I heard a voice from heaven saying, ‘Write this: Blessed are the dead who from now on die in the Lord.’ ‘Yes,’ says the Spirit, ‘they will rest from their labours, for their deeds follow them.’"
Revelation 20:13: "All the dead were judged according to their deeds."
Revelation 22:12: "Behold, I am coming soon. I bring with me the recompense I will give to each according to his deeds."
Works of the Law
Many Catholics see the exclusion of "works of the law" as only referring to works done for salvation under the Mosaic law, versus works of faith which are held as meritorious for salvation.
Adherents of sola fide respond that Jesus was not instituting keeping a higher moral code as means of salvation, and tend to see the exclusion of "works of the law" (as the means of obtaining justification) as referring to any works of the Mosaic law, and by implication, any "works of righteousness which we have done" (Titus 3:5) or any system in which one earns eternal life on the basis of the merit of works.
However, most understand that the "righteousness of the law" is to be fulfilled by those who are justified by faith (Romans 8:4). The Mosaic law and the principles of the Gospel (such as the Sermon on the Mount and the Last Judgment of Matthew 25) are seen as being in correspondence, with the latter fulfilling, clarifying, and expanding on the former, centering on God's love for us, and love to others. Thus a Protestant believer can claim that "the law is holy, and the commandment holy, and just, and good," (Romans 7:12) harmonizing the two principles of the same Bible.
Process or Event
Type of Action
Justification & Sanctification
Can be lost via mortal sin
Part of the same process
Can be lost via loss of faith
Justification is separate from and occurs prior to sanctification
There are several Church Fathers whom Protestant apologists believe taught the doctrine of Sola Fide (although Catholic and Orthodox apologists quote the same fathers as supporting a justification that includes works). Here are some of them:
“And we [Christians], too, being called by His will in Christ Jesus, are not justified by ourselves, nor by our own wisdom, or understanding, or godliness, or works which we have wrought in holiness of heart; but by that faith through which, from the beginning, Almighty God has justified all men; to whom be glory for ever and ever. Amen.”
in his Dialogue with Trypho: “No longer by the blood of goats and of sheep, or by the ashes of a heifer . . . are sins purged, but by faith, through the blood of Christ and his death, who died on this very account.”
“…a person is saved by grace, not by works but by faith. There should be no doubt but that faith saves and then lives by doing its own works, so that the works which are added to salvation by faith are not those of the law but a different kind of thing altogether.”
“Let him who boasts boast in the Lord, that Christ has been made by God for us righteousness, wisdom, justification, redemption. This is perfect and pure boasting in God, when one is not proud on account of his own righteousness but knows that he is indeed unworthy of the true righteousness and is (or has been) justified solely by faith in Christ.”
“Therefore let no one boast of his works, because no one can be justified by his works; but he who is just receives it as a gift, because he is justified by the washing of regeneration. It is faith, therefore, which delivers us by the blood of Christ, because blessed is he whose sins are forgiven, and to whom pardon is granted.”
For Scripture says that faith has saved us. Put better: Since God willed it, faith has saved us. Now in what case, tell me, does faith save without itself doing anything at all? Faith’s workings themselves are a gift of God, lest anyone should boast. What then is Paul saying? Not that God has forbidden works but that he has forbidden us to be justified by works. No one, Paul says, is justified by works, precisely in order that the grace and benevolence of God may become apparent.
If Abraham was not justified by works, how was he justified? … Abraham believed God, and it was reckoned to him as righteousness (Rom. 4:3; Gen. 15:6). Abraham, then, was justified by faith. Paul and James do not contradict each other: good works follow justification.
“When someone believes in him who justifies the impious, that faith is reckoned as justice to the believer, as David too declares that person blessed whom God has accepted and endowed with righteousness, independently of any righteous actions (Rom 4:5-6). What righteousness is this? The righteousness of faith, preceded by no good works, but with good works as its consequence.”
For we are justified by faith, not by works of the law, as Scripture says (Gal. 2:16). By faith in whom, then, are we justified? Is it not in him who suffered death according to the flesh for our sake? Is it not in one Lord Jesus Christ?
The Council of Trent sought to counter Reformation and clarify the Catholic Church's teaching on justification and the manner in which it differs from Lutherans and other Protestant traditions, stating that the believer is,
"justified by the good works that he performs by the grace of God and the merit of Jesus Christ."
"nothing further is wanting to the justified [baptized and faithful], to prevent their being accounted to have, by those very works which have been done in God, fully satisfied the divine law according to the state of this life, and to have truly merited eternal life."
“Hence, to those who work well unto the end and trust in God, eternal life is to be offered, both as a grace mercifully promised to the sons of God through Christ Jesus, and as a reward promised by God himself, to be faithfully given to their good works and merits.”
"If any one saith, that the justice received is not preserved and also increased before God through good works; but that the said works are merely the fruits and signs of Justification obtained, but not a cause of the increase thereof; let him be anathema."
"If any one saith, that by faith alone the impious is justified; in such wise as to mean, that nothing else is required to co-operate in order to the obtaining the grace of Justification, and that it is not in any way necessary, that he be prepared and disposed by the movement of his own will; let him be anathema." 
The Catholic Catechism teaches, "Moved by the Holy Spirit, we can merit for ourselves and for others the graces needed for our sanctification and for the attainment of eternal life."
In response to sola fide, Robert Sungenis argues in his book Not by Faith Alone, that
A thorough study of his epistles reveals that Paul used the word faith and its cognates over two hundred times in the New Testament, but not once did he couple them with the adjectival qualifiers alone or only. Are we to believe that though he intended to teach justification by faith alone, he was never convinced that he should employ the attributes of the word alone to express explicitly what he invariably meant? What would have curtailed him from such an important qualification if indeed the solitude of faith in regard to justification was on the forefront of his mind? A second reason that leads us to pose this critical question is that Paul used the word alone more frequently than did any other New Testament writer. Many of these instances appear right alongside the very contexts that contain teachings on faith and justification. Thus it is obvious that even while Paul was teaching about the nature of justification he was keenly aware of the word alone and its qualifying properties. This would lead us to expect that if Paul, who is usually very direct and candid in his epistles, wanted to teach unambiguously and unequivocally that man was justified by faith alone, he would be compelled to use the phrase if he thought it would make his point indisputable. Moreover, since Paul's writings were inspired, we must also acknowledge that the Holy Spirit likewise knew of the inherent qualifying properties of the word alone but had specific reasons for prohibiting Paul from using it in connection with faith.
We are accounted righteous before God, only for the merit of our Lord and Saviour Jesus Christ by faith, and not for our own works or deservings. Wherefore that we are justified by faith only is a most wholesome doctrine, and very full of comfort; as more largely is expressed in the Homily of Justification.
However, certain Anglican and Episcopal theologians (especially Anglo-Catholics) argue for a faith characterized by faithfulness, where good works and the Sacraments play an important role in the life of the Christian believer. (See New Perspective on Paul)
Article IV Of Justification
Our churches by common consent...teach that men cannot be justified before God by their own strength, merits, or works, but are freely justified for Christ's sake, through faith, when they believe that they are received into favor, and that their sins are forgiven for Christ's sake, who, by His death, has made satisfaction for our sins. This faith God imputes for righteousness in His sight. Rom. 3 and 4.
Justification is God's gracious and full acquittal upon principles of His righteousness of all sinners who repent and believe in Christ. Justification brings the believer unto a relationship of peace and favor with God.
That those which have union with Christ, are justified from all their sins, past, present, and to come, by the blood of Christ; which justification we conceive to be a gracious and free acquittance of a guilty, sinful creature, from all sin by God, through the satisfaction that Christ hath made by his death; and this applied in the manifestation of it through faith.
Salvation is variously expressed, sometimes as "justification by faith," in which case it means that the just person has accepted the offer of a covenantal relationship, and lives according to that covenant.
Article 23: The Justification of Sinners
We believe that our blessedness lies in the forgiveness of our sins because of Jesus Christ, and that in it our righteousness before God is contained, as David and Paul teach us when they declare that man blessed to whom God grants righteousness apart from works.
And the same apostle says that we are justified "freely" or "by grace" through redemption in Jesus Christ. And therefore we cling to this foundation, which is firm forever, giving all glory to God, humbling ourselves, and recognizing ourselves as we are; not claiming a thing for ourselves or our merits and leaning and resting on the sole obedience of Christ crucified, which is ours when we believe in him.
That is enough to cover all our sins and to make us confident, freeing the conscience from the fear, dread, and terror of God's approach, without doing what our first father, Adam, did, who trembled as he tried to cover himself with fig leaves.
In fact, if we had to appear before God relying—no matter how little—on ourselves or some other creature, then, alas, we would be swallowed up.
Therefore everyone must say with David: "Lord, do not enter into judgment with your servants, for before you no living person shall be justified."
Belgic Confession 1561 (French revision, 1619)
Question 86: Since then we are delivered from our misery, merely of grace, through Christ, without any merit of ours, why must we still do good works?
Answer: Because Christ, having redeemed and delivered us by his blood, also renews us by his Holy Spirit, after his own image; that so we may testify, by the whole of our conduct, our gratitude to God for his blessings, and that he may be praised by us; also, that every one may be assured in himself of his faith, by the fruits thereof; and that, by our godly conversation others may be gained to Christ.
Question 87: Cannot they then be saved, who, continuing in their wicked and ungrateful lives, are not converted to God?
Answer: By no means; for the holy scripture declares that no unchaste person, idolater, adulterer, thief, covetous man, drunkard, slanderer, robber, or any such like, shall inherit the kingdom of God.
Heidelberg Catechism 1563
I. Those whom God effectually calls, He also freely justifies; not by infusing righteousness into them, but by pardoning their sins, and by accounting and accepting their persons as righteous; not for any thing wrought in them, or done by them, but for Christ's sake alone; nor by imputing faith itself, the act of believing, or any other evangelical obedience to them, as their righteousness; but by imputing the obedience and satisfaction of Christ unto them, they receiving and resting on Him and His righteousness by faith; which faith they have not of themselves, it is the gift of God.
We believe we are never accounted righteous before God through our works or merit, but that penitent sinners are justified or accounted righteous before God only by faith in our Lord Jesus Christ.
Article IX—Justification and Regeneration (The Discipline of The Evangelical United Brethren Church 1963)
We are accounted righteous before God only for the merit of our Lord and Saviour Jesus Christ, by faith, and not for our own works or deservings. Wherefore, that we are justified by faith, only, is a most wholesome doctrine, and very full of comfort.
Article IX—Of the Justification of Man (The Articles of Religion of the Methodist Episcopal Church, the Discipline of 1808)
The justification of the sinner solely by the grace of God through faith in Christ crucified and risen from the dead.
British Evangelical Alliance Statement of Faith
We believe in...the Salvation of lost and sinful man through the shed blood of the Lord Jesus Christ by faith apart from works, and regeneration by the Holy Spirit...
World Evangelical Alliance Statement of Faith
Unofficial Ecumenical statements
The New Testament makes it clear that the gift of salvation is received through faith. "By grace you have been saved through faith; and this is not your own doing, it is the gift of God" (Ephesians 2:8). By faith, which is also the gift of God, we repent of our sins and freely adhere to the gospel, the good news of God's saving work for us in Christ. By our response of faith to Christ, we enter into the blessings promised by the gospel. Faith is not merely intellectual assent but an act of the whole persons involving the mind, the will, and the affections, issuing in a changed life. We understand that what we here affirm is in agreement with what the Reformation traditions have meant by justification by faith alone (sola fide).
The Gift of Salvation (1997)
Lutheran World Federation and the Roman Catholic Church
4.3 Justification by Faith and through Grace
25. We confess together that sinners are justified by faith in the saving action of God in Christ. By the action of the Holy Spirit in Baptism, they are granted the gift of salvation, which lays the basis for the whole Christian life. They place their trust in God's gracious promise by justifying faith, which includes hope in God and love for him. Such a faith is active in love and thus the Christian cannot and should not remain without works. But whatever in the justified precedes or follows the free gift of faith is neither the basis of justification nor merits it.
5. Regarding the way in which salvation is appropriated by the believers, Lutherans, by teaching that justification and salvation are by grace alone through faith (sola gratia, sola fide), stress the absolute priority of divine grace in salvation. When they speak about saving faith they do not think of the dead faith which even the demons have (cf. James 2:19), but the faith which Abraham showed and which was reckoned to him as righteousness (cf. Gen. 15:6, Rom. 4:3,9). The Orthodox also affirm the absolute priority of divine grace. They underline that it is God's grace which enables our human will to conform to the divine will (cf. Phil 2:13) in the steps of Jesus praying, "not as I will but as You will" (Matthew 26:39), so that we may work out our salvation in fear and trembling (cf. Phil. 2:12). This is what the Orthodox mean by "synergy" (working together) of divine grace and the human will of the believer in the appropriation of the divine life in Christ. The understanding of synergy in salvation is helped by the fact that the human will in the one person of Christ was not abolished when the human nature was united in Him with the divine nature, according to the Christological decisions of the Ecumenical Councils. While Lutherans do not use the concept of synergy, they recognize the personal responsibility of the human being in the acceptance or refusal of divine grace through faith, and in the growth of faith and obedience to God. Lutherans and Orthodox both understand good works as the fruits and manifestations of the believer's faith and not as a means of salvation.
^Wriedt, Markus. "Luther's Theology," in The Cambridge Companion to Luther. New York: Cambridge University Press, 2003, 88–94.
^Selected passages from Martin Luther, "Commentary on Galatians (1538)" as translated in Herbert J. A. Bouman, "The Doctrine of Justification in the Lutheran Confessions," Concordia Theological Monthly 26 (November 1955) No. 11:801. ctsfw.edu
^Titus 3:5, Engelder, T.E.W., Popular Symbolics. St. Louis: Concordia Publishing House, 1934, p.87 Part XXIII. "Baptism", paragraph 118.
^Eph. 2:8, Engelder, T.E.W., Popular Symbolics. St. Louis: Concordia Publishing House, 1934, p.57 Part XV. "Conversion", paragaph 78.
^“daily we sin, daily we are justified” from the Disputation Concerning Justification (1536) ISBN 0-8006-0334-6
^"History of the Christian Church, book 7, chapter 4".; Philip Schaff's The Protestant Spirit of Luther’s Version: "The most important example of dogmatic influence in Luther’s version is the famous interpolation of the word alone in Rom. 3:28 (allein durch den Glauben), by which he intended to emphasize his solifidian doctrine of justification, on the plea that the German idiom required the insertion for the sake of clearness. But he thereby brought Paul into direct verbal conflict with James, who says (James 2:24), "by works a man is justified, and not only by faith" ("nicht durch den Glauben allein"). It is well known that Luther deemed it impossible to harmonize the two apostles in this article, and characterized the Epistle of James as an "epistle of straw," because it had no evangelical character ("keine evangelische Art")."
^Joseph A. Fitzmyer Romans, "A New Translation with introduction and Commentary," The Anchor Bible Series (New York: Doubleday, 1993) 360-361
^"Luther, An Introduction to St. Paul's Letter to the Romans". Luther's German Bible of 1522 by Martin Luther, 1483-1546. iclnet.org. Translated by Rev. Robert E. Smith from Dr. Martin Luther's vermischte deutsche Schriften. Johann K. Irmischer, ed. Vol. 63 (Erlangen: Heyder and Zimmer, 1854), pp.124-125. [EA 63:124-125] August 1994
^Catechism of the Catholic church, Part 3, Life in Christ, Merit, 2010
^Catechism of the Catholic Church No. 1992. Vatican City-State. "Justification is conferred in Baptism, the sacrament of faith."
^Catechism of the Catholic Church No. 1446. The Vatican. "Christ instituted the sacrament of Penance for all sinful members of his Church: above all for those who, since Baptism, have fallen into grave sin, and have thus lost their baptismal grace and wounded ecclesial communion. It is to them that the sacrament of Penance offers a new possibility to convert and to recover the grace of justification. The Fathers of the Church present this sacrament as "the second plank [of salvation] after the shipwreck which is the loss of grace.""