Exodus 39:21-23

International Standard Version

²¹ They tied the breast piece by its rings to the rings of the ephod with a blue cord so it would rest on the skillfully woven band of the ephod and so the breast piece would not come loose from the ephod.

The Robe of the Ephod

²² He made the robe of the ephod of woven work, entirely of blue. ²³ The opening of the robe was in the middle, like the opening of a coat of mail, with a binding around the opening so it would not be torn.