Priesthood of all believers in the context of "Protestant"

Protestantism is a branch of Christianity that emphasizes justification of sinners through faith alone, the teaching that salvation comes by unmerited divine grace, the priesthood of all believers, and the Bible as the sole infallible source of authority for Christian faith and practice. The five solae summarize the basic theological beliefs of mainstream Protestantism.

Protestants follow the theological tenets of the Protestant Reformation, a movement that began in the 16th century with the goal of reforming the Catholic Church from perceived errors, abuses, and discrepancies. The Reformation began in the Holy Roman Empire in 1517, when Martin Luther published his Ninety-five Theses as a reaction against abuses in the sale of indulgences by the Catholic Church, which purported to offer the remission of the temporal punishment of sins to their purchasers. Luther's statements questioned the Catholic Church's role as negotiator between people and God, especially when it came to the indulgence arrangement, which in part granted people the power to purchase a certificate of pardon for the penalization of their sins. Luther argued against the practice of buying or earning forgiveness, claiming instead that salvation is a gift God gives to those who have faith.

The priesthood is the office of the ministers of religion, who have been commissioned ("ordained") with the holy orders of the Catholic Church. Technically, bishops are a priestly order as well; however, in common English usage priest refers only to presbyters and pastors (parish priests). The church's doctrine also sometimes refers to all baptised members (inclusive of the laity) as the "common priesthood", which can be confused with the ministerial priesthood of the ordained clergy.

The church has different rules for priests in the Latin Church–the largest Catholic particular church–and in the 23 Eastern Catholic Churches. Notably, priests in the Latin Church must take a vow of celibacy, whereas most Eastern Catholic Churches permit married men to be ordained. Deacons are male and usually belong to the diocesan clergy, but, unlike almost all Latin Church (Western Catholic) priests and all bishops from Eastern or Western Catholicism, they may marry as laymen before their ordination as clergy. The priesthood is a vocation for men; a similar but distinct vocation for women is the sisterhood. The Catholic Church teaches that when a man participates in priesthood after the Sacrament of Holy Orders, he acts in persona Christi Capitis, representing the person of Christ.

Quakers are people who belong to the Religious Society of Friends, originally known as simply the Society of Friends, a historically Protestant Christian set of denominations. Members refer to each other as Friends after John 15:14 in the Bible. Originally, others referred to them as Quakers because the founder of the movement, George Fox, told a judge to "quake before the authority of God".

The Friends are generally united by a belief in each human's ability to be guided by the inward light to "make the witness of God" known to everyone. Quakers have traditionally professed a priesthood of all believers inspired by the First Epistle of Peter. They include those with evangelical, holiness, liberal, and traditional Quaker understandings of Christianity, as well as Nontheist Quakers. To differing extents, the Friends avoid creeds and hierarchical structures. In 2017, there were an estimated 377,557 adult Quakers, 49% of them in Africa followed by 22% in North America.