Exodus 40:12-15

And thou shalt bring Aaron and his sons unto the door of the tent of meeting, and shalt wash them with water. And thou shalt put upon Aaron the holy garments; and thou shalt anoint him, and sanctify him, that he may minister unto me in the priest’s office. And thou shalt bring his sons, and put coats upon them; and thou shalt anoint them, as thou didst anoint their father, that they may minister unto me in the priest’s office: and their anointing shall be to them for an everlasting priesthood throughout their generations.