Exodus 28:30 says, “And you shall put in the breastplate of judgment the Urim and the Thummim, and they shall be upon Aaron’s heart when he goes in before Jehovah.” In David Baron’s book The Ancient Scriptures and the Modern Jew there is an appendix containing an article on the Urim and the Thummim. According to this article, the twelve names on the breastplate included eighteen of the twenty-two letters in the Hebrew alphabet. The remaining four letters were put on a piece called the Thummim. The Hebrew word Thummim means perfecters or completers. Thus, on the breastplate with the additional piece called the Thummim all twenty-two letters of the Hebrew alphabet could be found. Just as the twenty-six letters of the English alphabet on the keys of a typewriter can be used to compose a word, phrase, sentence, or paragraph, so the twenty-two letters of the Hebrew alphabet on the breastplate and the Thummim could be used to spell out words and sentences.
Furthermore, according to this article, the Urim was an illuminator inserted into the breastplate underneath the twelve stones. In Hebrew the word Urim means lights. This article in David Baron’s book says that the Urim had the capacity to contain oil for burning and that the fire used to burn this oil came from the altar. The Hebrew scholar responsible for this article also said that this Urim had twelve illuminators, one to illuminate each piece of stone on the breastplate. Then the transparent stones could shine with light.
When the Urim and the Thummim were added to the breastplate, they caused it to become the breastplate of judgment. Before they were added, the breastplate was simply for a memorial.
When God brought His people into the wilderness, He spoke to them through Moses. God spoke to Moses face to face. But after the death of Moses, Joshua received guidance from God not by His direct speaking in the way He spoke to Moses, but by the Urim and the Thummim on the breastplate worn by the high priest. Hence, whenever Joshua needed guidance concerning the move of the people, he had to go to the high priest who then received guidance from God by means of the Urim and the Thummim. Thus, God spoke through the Urim and the Thummim.
The writer of this article illustrates the function of the Urim and Thummim by referring to the case of Joshua and Achan. The children of Israel were defeated at Ai due to the sin of Achan (Josh. 7). How was Achan’s sin discovered? According to this article, a representative of each of the twelve tribes came to the tabernacle and stood before the high priest, who was wearing the breastplate. Suddenly one of the twelve pieces on the breastplate became dark. That was the stone for the tribe of Judah. In this way Judah was singled out. Joshua 7:16-18 says, “And the tribe of Judah was taken: And he brought the family of Judah; and he took the family of the Zarhites: and he brought the family of the Zarhites man by man; and Zabdi was taken: And he brought his household man by man; and Achan, the son of Carmi, the son of Zabdi, the son of Zerah, of the tribe of Judah, was taken.” It was also by the darkening of certain stones on the breastplate that the family and eventually the person were found out. In this situation the breastplate functioned like a spiritual and heavenly typewriter to spell out the name of Achan.
This article cites other instances of the use of the Urim and the Thummim. It says that Joshua allotted the land to the tribes through the Urim and the Thummim (Josh. 18:6-10), and also fought against the enemies according to the guidance of God made known by the Urim and the Thummim (Judg. 1:1-12; 20:18, 27; see Num. 27:21). Furthermore, when Saul the king became unfaithful to God, God would no longer answer him through the Urim and the Thummim (1 Sam. 28:6). When the priests were slain by Saul, one of the sons escaped to David, and David then followed the Lord by the Urim and the Thummim.
We have pointed out that the breastplate was called the breastplate of judgment. Deuteronomy 33:8 and 10 say, “And of Levi he said, Let thy Thummim and thy Urim be with thy holy one....They shall teach Jacob thy judgments, and Israel thy law.” Because the Urim and the Thummim were with the Levites, the priests, they could teach the people not only the law of God, but also His judgments.
What we have covered thus far regarding the Urim and the Thummim are some of the historical facts according to scholarship. We have not yet seen anything concerning the spiritual application of the Urim and the Thummim. It is not my burden in this message to speak about historical facts; rather, it is to show the spiritual application.