Exodus 29:8-11

8And thou shalt bring his sons, and put coats upon them.

9And thou shalt gird them with waistbands, Aaron and his sons, and put the headdresses on them: and the priest’s office shall be theirs for a perpetual statute: and thou shalt consecrate Aaron and his sons.12

10And thou shalt cause a bull to be brought before the tabernacle of the congregation: and Aaron and his sons shall put their hands upon the head of the bull.

11And thou shalt kill the bull before the LORD, by the door of the tabernacle of the congregation.