Exodus 39:19

16 And they made two gold frames and two gold rings, the rings being fixed to the ends of the priest's bag;

17 And they put the two twisted chains on the two rings at the ends of the priest's bag;

18 And the other two ends of the chains were joined to the two frames and fixed to the front of the ephod over the arm-holes.

19 And they made two rings of gold and put them on the two lower ends of the bag, on the inner side nearest to the ephod.

20 And two other gold rings were put on the front of the ephod, over the arm-holes, at the join, and over the worked band.

21 And the rings on the bag were fixed to the rings of the ephod by a blue cord, keeping it in place over the band, so that the bag might not get loose, as the Lord gave orders to Moses.

22 The robe which went with the ephod was made all of blue;