Keys of the Aaronic Priesthood
Doctrine and Covenants 13:1
1 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; and this shall never be taken again from the earth, until the sons of Levi do offer again an offering unto the Lord in righteousness.
Elder Hyrum M. Smith and Janne M. Sjödahl wrote:
“There are two priesthoods, the Melchizedek and the Aaronic, but ‘the Melchizedek Priesthood comprehends the Aaronic or Levitical Priesthood’ [Teachings of Presidents of the Church: Joseph Smith (2007), 108.] Moses held the Melchizedek Priesthood, ‘and sought diligently to sanctify his people . . . but they hardened their hearts . . . therefore, he took Moses out of their midst, and the Holy Priesthood also; and the lesser priesthood continued’ [D&C 84:23–27]. This lesser or Aaronic Priesthood holds the keys; that is, it has and confers authority to receive the ministration of angels, to preach the gospel of repentance, to baptize for the remission of sins, and to administer ‘the law of carnal commandments’ [D&C 84:27]. Those who held this priesthood in the Old [Mosaic] Dispensation attended to the Tabernacle and the Temple service, including the sacrifices; they took care of everything belonging to the Sanctuary. The duties of that priesthood are of a similar nature now.”
(The Doctrine and Covenants Commentary, rev. ed. , 69.)