Exodus 28:30

28:30 “You are to put the Urim and the Thummim into the breastpiece of decision; and they are to be over Aaron’s heart when he goes in before the Lord. Aaron is to bear the decisions of the Israelites over his heart before the Lord continually.

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.