Exodus 39:20-22

Lexham English Bible

²⁰ And they made two gold rings and put them on the ephod’s two shoulder pieces below, at its front near its seam above the waistband of the ephod. ²¹ And they tied the breast piece by its rings to the rings of the ephod with a blue cord so that the breast piece would be on the waistband of the ephod and not come loose from the ephod, as Yahweh had commanded Moses.

²² And he made the robe of the ephod, weaver’s work, totally of blue yarn.