Exodus 39:19-21

New King James Version

¹⁹ And they made two rings of gold and put them on the two ends of the breastplate, on the edge of it, which was on the inward side of the ephod. ²⁰ They made two other gold rings and put them on the two shoulder straps, underneath the ephod toward its front, right at the seam above the intricately woven band of the ephod. ²¹ And they bound the breastplate by means of its rings to the rings of the ephod with a blue cord, so that it would be above the intricately woven band of the ephod, and that the breastplate would not come loose from the ephod, as the Lord had commanded Moses.