Urim
and Thummim
are Hebrew words which literally mean lights and perfection, respectively. They seem to be some kind of mechanism which revealed God’s will. They were capable of giving a positive, negative, or neutral reply to a specific question. The Urim and Thummim were consulted on various occasions in early Israel, but by post-exilic times they had dropped out of use (Numbers 27:21; Deuteronomy 33:8; 1 Samuel 14:41).
8 And he placed the breastpiece on him, and in the breastpiece he put the Urim and the Thummim.