Q: #133. What were the Urim and Thummim?
A: The Urim (meaning “light”) and the Thummim (meaning “perfection) are mentioned only 7 times in the Bible (Ex 28:30)(Lev 8:8)(Num 27:21)(Deut 33:8)(1 Sam 28:6)(Ezra 2:63)(Neh 7:65). No one knows exactly what they looked like or how they were used, but we do know that they were used in some way to inquire of the Lord and seek His will. They were to be used only by the High Priest, and carried in a pouch attached to his breastplate and covering his heart (Ex 28:30).
According to tradition, there may have been two of them made of stone, with the Urim having “yes” written on it and the Thummim having “no.” A question would be asked of God in a way where a yes or no answer could be given. The High Priest would then either reach into the pouch and pull one out or possibly turn the bag upside down and pick the one that dropped first. They would then act according to the answer that God would supernaturally supply.
After the death of David, and the exile of both Israel and Judah, they are never shown to be used again, although they may have been (Ezra 2:63)(Neh 7:65).
Although not mentioned specifically as the Urim and Thummim, there may also have been a few other places where they were used as well: (Josh 7:14-18)(Judg 20:18,28)(1 Sam 14:36-43)(1 Sam 23:2,4,9-12)(2 Sam 2:1). Some also believe that the disciples may have used the Urim and Thummim to pick Matthias to replace Judas (Acts 1:26), although I personally find this unlikely.