Exodus 28:15

Exo 28:15 And thou shalt make the breastplate of judgment with cunning work; after the work of the ephod thou shalt make it; [of] gold, [of] blue, and [of] purple, and [of] scarlet, and [of] fine twined linen, shalt thou make it.

Ver. 15. The breastplate of judgment. ] So called because the priest was to put it on when he was to inquire and give sentence as from God. Num 27:21