Exodus 40:12-15

Then you shall bring Aaron and his sons to the doorway of the tent of meeting and wash them with water. You shall put the holy garments on Aaron and anoint him and consecrate him, that he may minister as a priest to Me. You shall bring his sons and put tunics on them; and you shall anoint them even as you have anointed their father, that they may minister as priests to Me; and their anointing will qualify them for a perpetual priesthood throughout their generations.”