Essay zu Schemot 28:6

This garment, which here seems to be a kind of apron worn only by the high priest, is mentioned elsewhere in the Bible in connection with worship (e.g., Judg. 8:27), but with unclear meaning. Even here, the exact nature of the efod is not entirely certain; but what is cited is its function as the setting for the stones that symbolize the twelve tribes of Israel in God’s presence. This is followed by a description of chains, whose use is mentioned immediately thereafter.