Deuteronomy 33:8

So he named the place Massah and Meribah because of the contending of the sons of Israel, and because they tested Yahweh, saying, “Is Yahweh among us or not?”

“You shall put in the breastpiece of judgment the Urim and the Thummim, and they shall be over Aaron’s heart when he comes in before Yahweh; and Aaron shall carry the judgment of the sons of Israel over his heart before Yahweh continually.

He then placed the breastpiece on him, and in the breastpiece he put the Urim and the Thummim.

And the governor said to them that they should not eat from the most holy things until a priest stood with Urim and Thummim.

“Instruction of truth was in his mouth, and unrighteousness was not found on his lips; he walked with Me in peace and uprightness, and he turned many back from iniquity.