Exodus 28:1

The Clothing of the Priests

28:1 “And you, bring near to you your brother Aaron and his sons with him from among the Israelites, so that they may minister as my priests – Aaron, Nadab and Abihu, Eleazar and Ithamar, Aaron’s sons.

Exodus 28:43

28:43 These must be on Aaron and his sons when they enter to the tent of meeting, or when they approach the altar to minister in the Holy Place, so that they bear no iniquity and die. It is to be a perpetual ordinance for him and for his descendants after him.

Exodus 29:20

29:20 and you are to kill the ram and take some of its blood and put it on the tip of the right ear of Aaron, on the tip of the right ear of his sons, on the thumb of their right hand, and on the big toe of their right foot, and then splash the blood all around on the altar.