'Urim and Thummim' in the Bible

Place the Urim and Thummim in the breastpiece for decisions, so that they will also be over Aaron’s heart whenever he comes before the Lord. Aaron will continually carry the means of decisions for the Israelites over his heart before the Lord.

Then he put the breastpiece on him and placed the Urim and Thummim into the breastpiece.

The governor told them that they should not eat of the most holy things [the priests’ food] until a priest stood up with Urim and Thummim [who by consulting these articles in his breastplate could determine God’s will in the matter].

And the Tirshatha said unto them, that they should not eat of the most holy things, till there stood up a priest with Urim and Thummim.