Their Use. It is notable that the Urim and the Thummim were to be over Aaron’s heart when he went “in before Jehovah,” doubtless referring to Aaron’s standing in the Holy before the curtain to the Most Holy compartment when inquiring of Jehovah. Their location, “over Aaron’s heart,” would appear to indicate that the Urim and the Thummim were placed in the fold, or pouch, formed by the doubled construction of the breastpiece. They were for “the judgments of the sons of Israel” and were used when a question of importance to the national leaders and consequently to the nation itself needed an answer from Jehovah. Jehovah, Israel’s Lawgiver, would give an answer to the high priest as to the right course to pursue on any matter.​—Ex 28:30.

A number of Bible commentators believe that the Urim and the Thummim were lots. They are called “the sacred lots” in James Moffatt’s translation of Exodus 28:30. Some suppose that they consisted of three pieces, one inscribed with the word “yes,” one with “no,” and the other blank. These would be drawn, giving the answer to the question propounded, unless the blank piece was drawn, in which case no answer was forthcoming. Others think that they may have been two flat stones, white on one side and black on the other. When thrown down, two white sides up would mean “yes,” two black sides “no,” and a black and a white would mean no answer. On one occasion, when Saul had inquired through the priest as to whether to resume an attack on the Philistines, he received no answer. Feeling that someone among his men had sinned, he petitioned: “O God of Israel, do give Thummim!” Saul and Jonathan were taken from among those present; after that, lots were cast to decide between the two. In this account the appeal, “Do give Thummim,” seems to be separate from the lot casting, though it may give indication that there was some connection between the two.​—1Sa 14:36-42.