Charles Ellicott Commentary Exodus 28:15

"And thou shalt make a breastplate of judgment, the work of the skilful workman; like the work of the ephod thou shalt make it; of gold, of blue, and purple, and scarlet, and fine twined linen, shalt thou make it." — Exodus 28:15 (ASV)

The breastplate of judgment. —The word khoshen does not really signify “breastplate,” but “ornament.” It was the main ornament of the priestly attire. It was called “the ornament of judgment” because it contained the Urim and Thummim, by which God’s “judgments” were made known to His people. (See Note on Exodus 28:30.)

With cunning work. —Rather, of the work of the weaver. (Exodus 26:31; Exodus 28:6.)