In his commentary on Exodus xxviii, Cornelius à Lapide (Cornelius Van den Steen) discusses the question of the diamond in the high-priest’s breastplate. In the first place, he notes that the diamond was very costly, and that a large stone would have been needed to bear the name of Judah or that of any other tribe. He considers that a stone of the requisite size would have cost a hundred thousand gold crowns, and he asks, “Whence could the poor Hebrews have obtained such a sum of money, and where could they have found such a diamond?” He proceeds to give still another reason for doubting that the diamond was in the breastplate,—namely, that it would have marked too great a distinction between the tribes, the result being that the tribe to which the diamond was assigned would have been puffed up with pride, while the others would have been filled with hatred and envy, “for the diamond is the Queen Gem of all the gems.”[414] The use of the breastplate to reveal the guilt of an offender is testified to in a Samaritan version of the book of Joshua, which has been discovered by Dr. Moses Gaster, chief rabbi of the Spanish and Portuguese Jews in England. According to this version, Achan steals a golden image from a heathen temple in Jericho. The high-priest’s breastplate reveals his guilt, for the stones lose their light and grow dim when his name is pronounced. Many conjectures have been made as to the origin of the breastplate with the mystic Urim and Thummim enclosed within it. That an Egyptian origin should be sought seems most probable. A breast-ornament worn by the high-priest of Memphis, as figured in an Egyptian relief, consists of twelve small balls, or crosses, intended to represent Egyptian hieroglyphics. As it cannot be determined that these figures were cut from precious stones, the only definite connection with the Hebrew ornament is the number of the figures; this suggests, but fails to prove, a common origin. The monuments show that the high-priest of Memphis wore this ornament as early as the fourth Dynasty, or, approximately, 4000 B.C.[415] Of the Urim and Thummim, the mysterious oracle of the ancient Hebrews, St. Augustine (354-450 A.D.), after acknowledging the great difficulty of interpreting the meaning of the words and the character of the oracle, adds that some believed the words to signify a single stone which changed color according as the answer was favorable or unfavorable, while the priest was entering the sanctuary; still he thought it possible that merely the letters of the words Urim and Thummin were inscribed upon the breastplate.[416]