Melchizedek – Fullness of Priesthood – by age 18

Encyclopedia of Mormonism

The Melchizedek Priesthood is the authority, responsibility, and power to act in the name of Jesus Christ and to organize and direct part of his work. Through the opportunities of this priesthood, men and women in partnership with God can conduct the work of the family and the Church. "It is the duty of this vast body of men holding the holy Priesthood…to exert their influence and exercise their power for good among the people of Israel and the people of the world…to preach and to work righteousness, both at home and abroad" (Smith, p. 157).

In the words of the Prophet Joseph Smith, "All Priesthood is Melchizedek, but there are different portions or degrees of it" (TPJS, p. 180). Most often, however, the name Melchizedek Priesthood is used in the Church to describe the higher priesthood and its offices. "There are, in the church, two priesthoods, namely, the Melchizedek and Aaronic…. The Melchizedek Priesthood holds the right of presidency, and has power and authority over all the offices in the church in all ages of the world, to administer in spiritual things" (D&C 107:1, 8). The Melchizedek Priesthood holds the keys to the kingdom, and "in the ordinances thereof, the power of godliness is manifest" (D&C 84:20).

ORDINATION TO THE MELCHIZEDEK PRIESTHOOD. Every faithful, worthy man in the Church may receive the Melchizedek Priesthood. As with the aaronic priesthood, the Melchizedek Priesthood is conferred on those who have qualified themselves and have been called by those in authority.