Doctrine and truth. Hebrew Urim and Thummim: illuminations and perfections. These words, written on the rational, seem to signify the light of doctrine, and the integrity of life, with which the priests of God ought to approach to him. (Challoner)

Aurim means things brilliant, “declarations,” Septuagint, and thomim, “perfections,” or “truths.” Some imagine, that God required the stones of the rational to be of the utmost brilliancy and perfection; Oleaster and Josephus (Antiquities iii. 8,) say, it was by the appearance of those stones that the high priest was enlightened, when he consulted God. If God approved of what was in agitation, they assumed a surprising brightness, as well as those on the high priest’s shoulders. But this had not happened for 200 years before he began his history. The Urim and Thummim were not in the second temple, 1 Esdras ii. 63. Some think these words were engraven on stones in the rational. Whether God explained his will by articulate sounds, as (Matthew iii. 17,) this is my beloved son, or internally instructed the high priest, when he was consulted, cannot be determined. (Calmet)

St. Chrysostom is of the former opinion. “If any thing was to be known, a voice came from between the cherubim, from the propitiatory, to declare what would happen.” As the Jews lost the propitiatory, when they were led captives to Babylon, it seems they never afterwards obtained this privilege of having an oracle. God sometimes instructed them by his prophets. But, for a long time, none had appeared; that all might attend more earnestly to the voice of the Messias. (Tirinus)

Judgment. He shall be the supreme judge in religious matters, and must strive to pass sentence according to the dictates of my law, with truth. (Haydock)

The chief judge in Egypt wore a golden chain, hanging from the neck on the breast, to which was attached the image of Truth, on a sapphire stone. Olian (Var. Hist. xxxiv. 14,) also observes, that this office was always held by a venerable and honest priest.