Exodus 39:21-23

American Standard Version

²¹ And they did bind the breastplate by the rings thereof unto the rings of the ephod with a lace of blue, that it might be upon the skilfully woven band of the ephod, and that the breastplate might not be loosed from the ephod; as Jehovah commanded Moses.

²² And he made the robe of the ephod of woven work, all of blue; ²³ and the hole of the robe in the midst thereof, as the hole of a coat of mail, with a binding round about the hole of it, that it should not be rent.