Exodus 40:12-15

Then you shall bring Aaron and his sons to the entrance of the tent of meeting and shall wash them with water and put on Aaron the holy garments. And you shall anoint him and consecrate him, that he may serve me as priest. You shall bring his sons also and put coats on them, and anoint them, as you anointed their father, that they may serve me as priests. And their anointing shall admit them to a perpetual priesthood throughout their generations.”