In the Church today, worthy male members may receive the Aaronic Priesthood beginning at age 12. These young men, typically ages 12–17, receive many opportunities to participate in sacred priesthood ordinances and give service. As they worthily fulfill their duties, they act in the name of the Lord to help others receive the blessings of the gospel.
As the Prophet Joseph Smith translated the Book of Mormon, he found mention of baptism for the remission of sins. On May 15, 1829, he and his scribe Oliver Cowdery went into the woods to inquire of the Lord concerning baptism. As they prayed, “a messenger from heaven descended in a cloud of light.” This messenger was John the Baptist, the prophet who had baptized Jesus Christ centuries earlier. John the Baptist, now a resurrected being, laid his hands on Joseph and on Oliver and conferred upon each of them the Aaronic Priesthood, which had been taken from the earth during the Great Apostasy. With this authority, Joseph and Oliver were able to baptize one another. (See Joseph Smith—History 1:68–72.)
The offices of the Aaronic Priesthood are bishop, priest, teacher, and deacon. With the authorization of the presiding priesthood leader (usually the bishop or branch president), deacons pass the sacrament. They help the bishop or branch president watch over Church members by giving service and assisting with temporal matters such as gathering fast offerings. Teachers may perform all the duties of deacons, and they also receive other opportunities to serve. They prepare the sacramental bread and water and serve as ministering brothers. Priests may perform all the duties of deacons and teachers. With the authorization of the presiding priesthood leader, they may also bless the sacrament, baptize, and ordain others to the offices of priest, teacher, and deacon.
The Aaronic Priesthood is “an appendage to the greater, or the Melchizedek Priesthood” (Doctrine and Covenants 107:14). It is often called the preparatory priesthood. As a priesthood holder serves in the Aaronic Priesthood, he prepares to receive the Melchizedek Priesthood, to receive the blessings of the temple, to serve a full-time mission, to be a loving husband and father, and to continue in lifelong service to the Lord.
“Aaronic Priesthood,” Encyclopedia of Mormonism