The Breastplate
Archimandrite Nikifor’s Biblical Encyclopedia
(the word of judgment) (Ex. 28:4, Lev. 8:8 and others)—a special garment worn on the breast of the high priest, with twelve various precious stones, on which were engraved the names of the twelve tribes of the sons of Israel (Ex. 28:15–30). The rings, chains, and other adornments which fastened the breastplate to the ephod were made of gold. The high priest was required to bear the names of the tribes of the sons of Israel on the breastplate over his heart, for a continual memorial of them before the Lord (Ex. 28:29, 30).
It was also called the breastplate of judgment (28:15), perhaps also because it was worn upon his breast by the high priest, so exalted a person, who was to be a source of righteousness and judgment for the Jewish church, and whose decisions, by divine inspiration, were always to be clear, just, and binding upon the Jews.