not be loosed from the Ephod" in that one who removed the breastplate from the apron received the punishment of lashes. Rav Aha bar Jacob objected that perhaps meant merely to instruct the Israelites to fasten the breast-plate securely so that it would "not be loosed." But the Gemara noted that does not say merely, "so that it not be loosed." The Mishnah taught that the High Priest inquired of the Urim and Thummim noted in only for the king, for the court, or for one whom the community needed. A Baraita explained why the Urim and Thummim noted in were called by those names: The term "Urim" is like the Hebrew word for "lights," and thus it was called "Urim" because it enlightened. The term "Thummim" is like the Hebrew word tam meaning "to be complete," and thus it was called "Thummim" because its predictions were fulfilled. The Gemara discussed how they used the Urim and Thummim: Rabbi Joḥanan said that the letters of the stones in the breastplate stood out to spell out the answer. Resh Lakish said that the letters joined each other to spell words. But the Gemara noted that the Hebrew letter , tsade, was missing from the list of the 12 tribes of Israel. Rabbi Samuel bar Isaac said that the stones of the breastplate also contained the names of Abraham, Isaac and Jacob. But the Gemara noted that the Hebrew letter , teth, was also missing. Rav Aha bar Jacob said that they also contained the words: "The tribes of Jeshurun." The Gemara taught that although the decree of a prophet could be revoked, the decree of the Urim and Thummim could not be revoked, as says, "By the judgment of the Urim." The Pirke De-Rabbi Eliezer taught that when Israel sinned in the matter of the devoted things, as reported in , Joshua looked at the 12 stones corresponding to the 12 tribes that were upon the High Priest's breastplate. For every tribe that had sinned, the light of its stone became dim, and Joshua saw that the light of the stone for the tribe of Judah had become dim. So Joshua knew that the tribe of Judah had transgressed in the matter of the devoted things. Similarly, the Pirke De-Rabbi Eliezer taught that Saul saw the Philistines turning against Israel, and he knew that Israel had sinned in the matter of