Exodus 29:8-11

8Then you shall bring his sons and put coats on them,

9and you shall gird Aaron and his sons with sashes and bind caps on them. And the priesthood shall be theirs by a statute forever. Thus you shall ordain Aaron and his sons.

10"Then you shall bring the bull before the tent of meeting. Aaron and his sons shall lay their hands on the head of the bull.

11Then you shall kill the bull before the Lord at the entrance of the tent of meeting,