Leviticus 8:8
7 Then he put the tunic on Aaron, wrapped the sash around him, and clothed him with the robe. Next he put the ephod on him and placed on him the decorated band of the ephod, and fastened the ephod closely to him with the band. 8 He then set the breastpiece on him and put the Urim and Thummim into the breastpiece. 9 Finally, he set the turban on his head and attached the gold plate, the holy diadem, to the front of the turban just as the Lord had commanded Moses.
Onkelos Leviticus 8:8
7 He put the tunic on Aaron, tied the sash around him, clothed him with the robe, and put the ephod on him, fastening it with the ephod’s waistband and securing it; 8 He placed the breastpiece on him, and in the breastpiece he put the Urim and Thummim. 9 He placed the turban on his head and attached the gold plate, the holy crown, on the front of the turban, as the Lord had commanded Moses.
Notes and References
"... The meaning of Urim and Thummim - parts of the 'breastpiece of judgment' mentioned also in Exodus 28:30 and Numbers 27:21 - is obscure. It was used in some unspecified and enigmatic way to seek answers from God. It may have contained the twenty-two letters of the Hebrew alphabet carved on twenty-two separate pieces of wood or metal. The priest may have lifted various letters randomly and combined them to form an answer to his questions by divine manipulation or inspiration. Its name begins with the first and last Hebrew letters (Babylonian Talmud, Yoma 73b.) The Bible relates several instances where the Urim and Thummim was used. In Samuel 14, for example, King Saul used it to discover who had disobeyed ..."
Drazin, Israel, and Stanley M. Wagner Onkelos on the Torah, Leviticus: Understanding the Bible Text (p. 50) Gefen, 2006