In the Latter Day Saint movement, priesthood is the power and authority of God given to man, including the authority to perform ordinances and to act as a leader in the church. A group of priesthood holders is referred to as a quorum.
Priesthood denotes elements of both power and authority. The priesthood includes the power Jesus gave his apostles to perform miracles such as the casting out of devils and the healing of sick (Luke 9:1). Latter Day Saints believe that the Biblical miracles performed by prophets and apostles were performed by the power of priesthood, including the miracles of Jesus, who holds all of the keys of the priesthood. The priesthood is formally known as the "Priesthood after the Order of the Son of God", but to avoid the too frequent use of the name of deity, the priesthood is referred to as the Melchizedek priesthood (Melchizedek being the high priest to whom Abraham paid tithes).
As an authority, priesthood is the authority by which a bearer may perform ecclesiastical acts of service in the name of God. Latter Day Saints believe that acts (and in particular, ordinances) performed by one with priesthood authority are recognized by God and are binding in heaven, on earth, and in the afterlife. In addition, Latter Day Saints believe that leadership positions within the church are legitimized by the priesthood authority. The Church of Jesus Christ of Latter-day Saints (LDS Church), the largest church in the movement, restricts its priesthood to men, as do most of the other Latter Day Saint denominations. An exception is the Community of Christ, the second largest denomination of the movement, which began ordaining women to all of its priesthood offices in 1984.
Orders of priesthood
Latter Day Saint theology has recognized at least three orders of priesthood: (1) the Aaronic priesthood, (2) the Melchizedek priesthood; and (3) the Patriarchal priesthood. Although these are different orders, they are, in reality, all subsumed under the priesthood held by Jesus Christ, that is, the Melchizedek priesthood.
The Aaronic priesthood (also called the Levitical priesthood), is considered to be a lesser priesthood tracing its roots to Aaron, the brother of Moses, through John the Baptist. In Latter Day Saint theology, it derives from the original holy priesthood which Joseph Smith and Oliver Cowdery received on May 15, 1829, when they were ordained by an angel identifying himself as John the Baptist. In 1835, Smith and Cowdery clarified that this authority was the "Aaronic, or Levitical priesthood".
By early 1831, Latter Day Saint theology also recognized a higher order of priesthood, or the high priesthood. This high priesthood had been foreshadowed in the Book of Mormon, which referred to men holding the unique position of high priest in the church organization described in that book, holding the "high priesthood of the holy order of God" (, ); however, the office of high priest was not implemented in early Mormonism until some days after Smith was joined in his ministry by Sidney Rigdon, a newly-converted Cambellite minister from Ohio, who merged his congregation with Smith's Church of Christ. Rigdon believed the teachings of the early Mormon missionaries who taught him, but thought the missionaries were lacking in heavenly power. In response to Rigdon's concern, the church's first high priests were ordained at a special conference held in June 1831.
By 1835, Latter Day Saints began referring to this high priesthood as the Melchizedek priesthood, or, the "Holy Priesthood, after the Order of the Son of God". This priesthood was so named, according to a revelation, because Melchizedek "was such a great high priest" and "out of respect or reverence to the name of the Supreme Being, to avoid the too frequent repetition of his name". This priesthood was thought to be the order of priesthood held by Jesus, and a distinction was made between the Aaronic and Melchizedek priesthoods, which derives in part from the Epistle to the Hebrews, whose author argues that Jesus arose "after the order of Melchizedec, and not ... after the order of Aaron" (Heb. 7:11).