The breast-plate of judgement— This breast-plate of judgement was the most superb and important of the high-priest's ornaments. It was called the breast-plate of judgement, because the high-priest wore it upon his breast when he went to ask counsel or judgement of the Lord, Exodus 28:29. The word is rendered by the LXX λογειον, the oracle; but the exact meaning of the original word is not determined. It was to be made of the same materials with the ephod: it was to be four-square, a span long, and a span broad; a span, that is, about nine inches; and it was to be double, most probably for the greater strength and convenience, as it was to hold the weight of twelve precious stones, with the names of the twelve tribes engraved upon them. It is not possible to determine whether the names of these stones be properly rendered. There are writers* who have laboured the subject very much, and to them we refer the reader desirous of further satisfaction; observing, that our translation is generally thought as judicious as any. In the description of the New Jerusalem, Revelation 21:19-20 there seems to be an allusion to these twelve stones in the high-priest's vestment.
* Lud. de Dieu, Braunius de Vest. Sac. Hebr.—Hill's Version of Theophrastus on Stones, &c.