The universal priesthood or the priesthood of all believers is a Christian doctrine stating that ordinary Christians share a common priesthood. The exact meaning of this belief and its implications varies from denomination to denomination.
It is a foundational concept of Protestantism. While Martin Luther did not use the exact phrase "priesthood of all believers", he adduces a general priesthood in Christendom in his 1520 To the Christian Nobility of the German Nation in order to dismiss the medieval view that Christians in the present life were to be divided into two classes: "spiritual" and "secular". He put forward the doctrine that all baptized Christians are "priests" and "spiritual" in the sight of God:
That the pope or bishop anoints, makes tonsures, ordains, consecrates, or dresses differently from the laity, may make a hypocrite or an idolatrous oil-painted icon, but it in no way makes a Christian or spiritual human being. In fact, we are all consecrated priests through Baptism, as St. Peter in 1 Peter 2[:9] says, "You are a royal priesthood and a priestly kingdom," and Revelation [5:10], "Through your blood you have made us into priests and kings."
How then if they are forced to admit that we are all equally priests, as many of us as are baptized, and by this way we truly are; while to them is committed only the Ministry (ministerium Predigtamt) and consented to by us (nostro consensu)? If they recognize this they would know that they have no right to exercise power over us (ius imperii, in what has not been committed to them) except insofar as we may have granted it to them, for thus it says in 1 Peter 2, "You are a chosen race, a royal priesthood, a priestly kingdom." In this way we are all priests, as many of us as are Christians. There are indeed priests whom we call ministers. They are chosen from among us, and who do everything in our name. That is a priesthood which is nothing else than the Ministry. Thus 1 Corinthians 4:1: "No one should regard us as anything else than ministers of Christ and dispensers of the mysteries of God."
But you are not like that, for you are a chosen people. You are royal priests, a holy nation, God’s very own possession. As a result, you can show others the goodness of God, for he called you out of the darkness into his wonderful light.
(This New Living Translation version reflects the Protestant view, as the universal "royal priesthood" from the Bible Luther cites above has been changed to individual "royal priests".)
"Scripture...sets before us Christ alone as mediator, atoning sacrifice, high priest, and intercessor."—Augsburg Confession Art. XXI.
In ancient Israel, priests acted as mediators between God and people. They ministered according to God's instruction and they offered sacrifices to God on behalf of the people. Once a year, the high priest would enter the holiest part of the temple and offer a sacrifice for the sins of all the people, including all the priests.
Although many religions use priests, most Protestant faiths reject the idea of a priesthood as a group that is spiritually distinct from lay people. They typically employ professional clergy who perform many of the same functions as priests such as clarifying doctrine, administering communion, performing baptisms, marriages, etc. In many instances, Protestants see professional clergy as servants acting on behalf of the local believers. This is in contrast to the priest, whom some Protestants see as having a distinct authority and spiritual role different from that of ordinary believers.
Most Protestants today recognize only Christ as a mediator between themselves and God (1 Timothy 2:5). The Epistle to the Hebrews calls Jesus the supreme "high priest," who offered himself as a perfect sacrifice (Hebrews 7:23–28). Protestants believe that through Christ they have been given direct access to God, just like a priest; thus the doctrine is called the priesthood of all believers. God is equally accessible to all the faithful, and every Christian has equal potential to minister for God. This doctrine stands in opposition to the concept of a spiritual aristocracy or hierarchy within Christianity.
The belief in the priesthood of all believers does not preclude order, authority or discipline within congregations or denominational organizations. For example, Lutheranism maintains the biblical doctrine of "the preaching office" or the "office of the holy ministry" established by God in the Christian Church. The Augsburg Confession states:
[From Article 4:] Furthermore, it is taught that we cannot obtain forgiveness of sin and righteousness before God through our merit, work, or satisfactions, but that we receive forgiveness of sin and become righteous before God out of grace for Christ’s sake through faith when we believe that Christ has suffered for us and that for his sake our sin is forgiven and righteousness and eternal life are given to us ... [From Article 5:] To obtain such faith God instituted the office of preaching, giving the gospel and the sacraments. Through these, as through means, he gives the Holy Spirit who produces faith, where and when he wills, in those who hear the gospel ... [Article 14:] Concerning church government it is taught that no one should publicly teach, preach, or administer the sacraments without a proper [public] call.
The origins of the doctrine within Protestantism are somewhat obscure. The idea was found in a radical form in Lollard thought. Martin Luther adduced it in his writings for the purpose of reforming the Christian Church, and it became a central tenet of Protestantism.
The doctrine is strongly asserted within Methodism and the Plymouth Brethren movement. Within Methodism it can plausibly be linked to the strong emphasis on social action and political involvement within that denomination. Within the Plymouth Brethren, the concept is most usually evidenced in the lack of distinction between "clergy" and "laity," the refusal to adopt formal titles such as Reverend or Bishop, the denial of formal ordination, and in some cases the refusal to hire any "professional staff" or paid Christian workers at all. Baptist movements, which generally operate on a form of congregational polity, also lean heavily on this concept. The Laestadianpietist movement has a specific interpretation of the doctrine as one of its solemn rites concerning forgiveness of sins.
The vast majority of Protestants nonetheless draw some distinction between their own ordained ministers and lay people. Pastors and ordained ministers are usually regarded as congregational leaders and theologians who are well versed with Christian liturgy, scripture, church teachings and are qualified to lead worship and preach sermons.
Some groups during the Reformation believed that priesthood authority was still needed, but was lost from the earth. Roger Williams believed, "There is no regularly constituted church of Christ on earth, nor any person qualified to administer any church ordinances; nor can there be until new apostles are sent by the Great Head of the Church for whose coming I am seeking." Another group, the Seekers, believed that the Roman Catholic Church had lost its authority through corruption and waited for Christ to restore his true church and authority.
The dogmatic constitution Lumen Gentium of the Second Vatican Council specifically highlights the priesthood of all believers. It teaches that the Church's relationship with God is independent of whatever ordination people have received, as evidenced by the guidelines and rubrics for personal prayer when no priest is present. Such Churches have always taught implicitly that a Christian's personal relationship with God is independent of whatever ordination they have received.
Thus, the Catholic Church accepts the 'priesthood of all believers' doctrine – it is not the exclusive domain of Protestantism. This is exemplified in 'chaplet of divine mercy' prayer, in which the individual Christian declares: "Eternal Father, I offer you the Body and Blood, Soul and Divinity, of your dearly beloved Son, our Lord Jesus Christ, in atonement for our sins..." The primary difference between the teachings of the Catholic Church and those of the (non-Anglican) Protestant churches that reject the ordained priesthood is that the Catholic Church believes in three different types of priests:
first, the priesthood of all believers (1 Peter 2:5–9);
second, the ordained priesthood (Acts 14:23, Romans 15:16, Titus 1:5); and
third, the high priesthood of Jesus (Hebrews 3:1).
Much of the doctrinal dispute on this matter is caused by the difference between the Greek words ἱερεύς (hiereus meaning "sacred one"; represented in Latin by the word sacerdos) and πρεσβύτερος (presbyteros meaning "one with elderhood"), which are usually both translated in English with the word "priest". The former term refers to the sacrificial ritual leaders of Judaism, the kohanim, and to those holding the office of conducting sacrifices in ancient pagan temples, whereas the latter term refers to an acknowledged elder of a community.
The earliest Christianity is not recorded as ever having created an office of hiereus, except to acknowledge Jesus in that role, and as in the Greek of 1 Peter 2:9, to recognize the Church as having it in a collective sense. The New Testament records the role of presbyter and/or bishop (or episkopos which literally means "overseer") in the earliest Christian churches as the role ordained by the Apostles to the earliest acknowledged leaders of the Church. Saying that all Christians are a "sacred one" (i.e. hiereus) is not to say that each Christian is "one with elderhood" (i.e. presbyteros).
The Catholic belief of sacerdotalism expresses the belief that only when led by those with true apostolic succession can sacraments be validly performed. This belief also tends to emphasize that sacerdos of all baptized Christians is held by all Christians together, not necessarily individually. Catholicism expresses the idea of the priesthood of all baptized Christians in English as the "common priesthood"; by parallel, they refer to Catholic clergy as the "ministerial priesthood". They defend this doctrine with the original languages of scripture and its prophecy. The Orthodox hold a very similar view.
^"Protestantism originated in the 16th-century Reformation, and its basic doctrines, in addition to those of the ancient Christian creeds, are justification by grace alone through faith, the priesthood of all believers, and the supremacy of Holy Scripture in matters of faith and order." "The Protestant Heritage" Encyclopædia Britannica. 2007. Encyclopædia Britannica Online. 20 Sept. 2007 
^Martin Luther, Weimar Ausgabe, vol. 6, p. 407, lines 19–25 as quoted in Timothy Wengert, "The Priesthood of All Believers and Other Pious Myths," page 12 .
^De captivitate Babylonica ecclesiae praeludium [Prelude concerning the Babylonian Captivity of the church], Weimar Ausgabe 6, 564.6–14 as quoted in Norman Nagel, "Luther and the Priesthood of All Believers," Concordia Theological Quarterly 61 (October 1997) 4:283-84.
^Articles 4, 5, and 14 of the Augsburg Confession in Robert Kolb and Timothy J. Wengert, trans. and eds., The Book of Concord : The Confessions of the Evangelical Lutheran Church, (Minneapolis: Fortress Press, 2000), 39, 40, 46.