Priest, Aaronic Priesthood See also Aaron, Brother of Moses; Aaronic Priesthood; High Priest An office of the Aaronic Priesthood. Anciently, the highest office in the Levitical Priesthood was held only by Aaron and his descendants. When Christ fulfilled the law of Moses, this restriction was removed. A priest’s duties in the restored Church are described, D&C 20:46–52.