Exodus 28:38

28:38 It will be on Aaron’s forehead, and Aaron will bear the iniquity of the holy things, which the Israelites are to sanctify by all their holy gifts; it will always be on his forehead, for their acceptance before the Lord.

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.