A priest or priestess is a holy man or woman who takes an officiating role in worship of any religion, with the distinguishing characteristic of offering sacrifices. Priests have been known since the earliest times and in the simplest societies (see shaman and oracle). There are priests in some branches of Christianity, Shintoism, Buddhism, Hinduism, and many, many others, though each culture has a local denomination for the priestly office. The term "priestess" is often used for female priests in neopagan religions such as the Lilian tradition, Wicca, and various reconstructionist faiths. Priests are generally regarded as having good contact with the deities of the religion he or she ascribes to, and other believers will often turn to a priest for advice on matters spiritual.
In many (but not all) religions, being a priest is a full time assignment, ruling out any other career. In many other religions it is a position inherited in familial line.
The position of a Kohen's
hands when he raises them to bless a Jewish congregation
In Judaism, the sub-tribe of the Kohanim (Cohen[s]) and the Levi'im (Levites) (Levy[s]), who are traditionally accepted as the descendants of Aaron, are hereditary priests through paternal descent.
During the times of the two Jewish Temples in Jerusalem they were responsible for daily and special Jewish holiday offerings and sacrifices within the temples known as the korbanot. Since the demise of the Second Temple, it has been the rabbis who became the most important members of the Jewish clergy.
However, the role of the Kohen is still extant, although much less important than in Biblical times. In Israel the Kohanim bless their congregations each day as part of the morning Jewish prayers services. Outside of Israel, they only do so on the Jewish holidays in the synagogues during morning prayers.
In the Christian context, some confusion is caused for English speakers by two different Greek words traditionally translated as priest. Both occur in the New Testament, which draws a distinction not always observed in English. The first, presbyteros (πρεσβυτερος), Latin presbyter, is traditionally translated priest and the English word priest is indeed a deformed pronunciation of this word; literally, it means elder. The second, hiereus ('ιερευς), Latin sacerdos, refers to priests who offer sacrifices, such as the priesthood of the Jewish Temple, or the priests of pagan gods. The Epistle to the Hebrews draws a distinction between the two types of priesthood; it teaches that atonement by Jesus Christ has made the hiereus or sacerdotal priesthood redundant, in terms of the sacrifices the Jews previously offered. Thus, Christ himself is the only hiereus for Christians. Catholics and Orthodox believe that there is a new priesthood in the sense of the presbyteros, which offers the one sacrifice of Jesus in the form of the Eucharist. At some point after the destruction of the Temple in Jerusalem (70 A.D.), however, Greek-speaking Christians also began using hiereus to refer to presbyters, but still making a distinction between the old priesthood and the new.
Thus, in Eastern Orthodoxy and Catholicism generally a priest is also called a "presbyter" or elder. Priests are considered clergy; a priest can only be ordained by a bishop and with the "axios" or affirmation of the laity of his parish.
In the Eastern and Roman traditions, only men may become priests; canonically the minimum age is 30 years of age, although exceptions are made from time to time at the bishop's discretion. As a general rule, priests cannot marry in the Latin rite of the Roman church, though married men may become priests in the Eastern Rites of the Roman church, and there are special rules for married clergy converting from certain other denominations. See clerical celibacy for more details of marriage rules in Roman Catholic and Orthodox churches. See Presbyterorum Ordinis for the decree on the priesthood from the Second Vatican Council, i.e. for a recent statement on the nature of the priesthood within the Roman Catholic faith.
Celibacy is not required of priests in the Orthodox, Anglican or Episcopalian Churches, but Orthodox priests are not allowed to marry after their ordinations, for example if their wife dies.
The most significant liturgical acts reserved to priests are the administration of the Sacraments, including the celebration of the Mass (see also Eucharist), Holy Baptism and the Sacrament of Reconciliation, a rite of Repentance, also called "Confession". The presence and ministry of a priest is required for a parish to function fully.
Some branches of Christianity, often within Protestantism, do not use the term "priest" to describe the individual who has an officiating role, because they do not believe in the idea of a sacrificial mass; instead, terms like "Minister" or "Pastor" are often used in its place. Lutheranism uses the term in Scandinavia and the Baltics and in churches deriving from there, but not in Germany and churches deriving from there. In most branches of the Anglican church both men and women can become priests and there are no restrictions on marriage.
Quakerism does not grant a special priestly role to any individual, partly because Quakers do not practice any special sacraments that require priestly mediation, and partly because they believe that the priesthood of all believers grants the potential of a spiritual and ministerial role to all individuals within the denomination, regardless of sex or status within the faith.
Roman Catholic, Anglican, many American Episcopalian, and some Lutheran priests and Protestant pastors and other clergy wear the stiff white clerical collar around the neck. Formally many clergy wore a clerical collar at all times; nowadays many only do so during duties at church, or in hospitals or other situations where instant recognition as a member of the clergy may be important.
Eastern Orthodox priests, when not celebrating a service, generally wear a long robe called a cassock, and many also wear a large cross, called a pectoral cross. (The cross is more often worn by priests in western countries to distinguish them as Christian.) As a general rule, the Slavic churches tend to give pectoral crosses to all priests, whereas those in the churches of Arabic and Greek descent (i.e., those from the "Byzantine" Empire) receive pectoral crosses only as an honorific token. Some Eastern Orthodox priests wear a collar similar to that of Western clergy, although this is falling out of favor since this leads to their being confused with Roman Catholic or Protestant clergy. When celebrating services, Orthodox priests always wear special liturgical vestments.