Exodus 39:20-21

CLV(i) 20 They made two rings of gold and put them on the two shoulderpieces of the vestment below its forefront view to correspond with its joining above to the designed band of the vestment. 21 Then they laced the breastplate by its rings to the rings of the vestment with blue twine, to come to be over the designed band of the vestment, so that the breastplate be not displaced from the vestment, just as Yahweh had instructed Moses.