Exodus 39:15-21

They made braided chains of pure gold for the Breastpiece, like cords. They made two settings of gold filigree and two rings of gold, put the two rings at the two ends of the Breastpiece, and fastened the two ends of the cords to the two rings at the end of the Breastpiece. Then they fastened the cords to the settings of filigree, attaching them to the shoulder pieces of the Ephod in front. Then they made two rings of gold and fastened them to the two ends of the Breastpiece on its inside edge facing the Ephod. They made two more rings of gold and fastened them in the front of the Ephod to the lower part of the two shoulder pieces, near the seam above the decorated band of the Ephod. The Breastpiece was fastened by running a cord of blue through its rings to the rings of the Ephod so that it rested secure on the decorated band of the Ephod and wouldn’t come loose, just as GOD had commanded Moses.