Exodus 39:17-21

Then they put the two gold cords in the two rings at the ends of the breastpiece.

And they put the other two ends of the two cords on the two filigree settings, and put them on the shoulder pieces of the ephod at the front of it.

They made two gold rings and placed them on the two ends of the breastpiece, on its inner edge which was next to the ephod.

Furthermore, they made two gold rings and placed them on the bottom of the two shoulder pieces of the ephod, on the front of it, close to the place where it joined, above the woven band of the ephod.

And they bound the breastpiece by its rings to the rings of the ephod with a violet cord, so that it would be on the woven band of the ephod, and that the breastpiece would not come loose from the ephod, just as the Lord had commanded Moses.