When Jesus Christ was on the earth, He established His Church and gave His Apostles the priesthood, which is the power to act in His name (see Luke 9:1–2). After His Crucifixion and the death of His Apostles, priesthood authority and the fulness of the gospel were taken from the earth because of wickedness and a rejection of the truth (see 2 Thessalonians 2:1–3).
In the early 1800s, Heavenly Father and Jesus Christ restored the gospel to the earth through the Prophet Joseph Smith. This Restoration included the restoration of priesthood power and authority
While Joseph Smith and Oliver Cowdery were working on the translation of the Book of Mormon, they read about baptism for the remission of sins. On May 15, 1829, they went to a wooded area near Joseph’s home in Harmony, Pennsylvania, and prayed about what they had learned.
In answer to their prayer, John the Baptist, under the direction of the Lord Jesus Christ, appeared and conferred upon them the Aaronic Priesthood, saying, “Upon you my fellow servants, in the name of Messiah I confer the Priesthood of Aaron, which holds the keys of the ministering of angels, and of the gospel of repentance, and of baptism by immersion for the remission of sins” (Doctrine and Covenants 13:1). Following John’s instructions, Joseph and Oliver then baptized each other and ordained each other to the Aaronic Priesthood (see Joseph Smith—History 1:68–72.)
Sometime after John the Baptist’s appearance, the ancient Apostles Peter, James, and John also appeared to Joseph and Oliver, again under the direction of Jesus Christ, and conferred upon them the Melchizedek Priesthood (see Doctrine and Covenants 128:20). “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” (Doctrine and Covenants 107:8). With this authority again on the earth, the Church of Jesus Christ could be restored in its fulness.
As part of the continuing restoration, additional priesthood keys were restored on April 3, 1836. The ancient prophets Moses, Elias, and Elijah appeared to Joseph Smith and Oliver Cowdery in the Kirtland Temple and committed the keys of their dispensations to them. Moses brought the keys of the gathering of Israel. Elias restored the keys of the gospel of Abraham. Elijah brought the sealing keys, which make it possible for families to be sealed together forever. (See Doctrine and Covenants 110.)
For additional information, read “The Restoration of the Fulness of the Gospel of Jesus Christ: A Bicentennial Proclamation to the World.”
“The Restoration of the Priesthood,” Youth Topics
“Where Was the Priesthood Restored?” Church History
“Priesthood Restoration Site,” Church History
“The Priesthood Is Restored,” Friend, February 2013
“Rejoice in the Restoration of the Priesthood and Priesthood Keys,” Ensign, April 2005
“The Restoration of the Aaronic and Melchizedek Priesthoods,” Ensign, December 1996