The Urim and Thummim were objects kept in the breastplate of the high priests and used for divining God’s will. In the Pentateuch they are associated with Levi (Deuteronomy 33:8), Aaron (Exodus 28:30; Leviticus 8:8), and Eleazar (Numbers 27:21). They were probably two small objects made of wood, bone, or stone, perhaps different colours, and having inscriptions that would give a yes or a no answer in response to a question. The high priest would reach into his breastplate and extract one of the objects.1
63 The governor told them that they were not to partake of the most holy food, until there should be a priest to consult Urim and Thummim.