Exodus 28:28

28:28 They are to tie the breastpiece by its rings to the rings of the ephod by blue cord, so that it may be above the waistband of the ephod, and so that the breastpiece will not be loose from the ephod.

Exodus 28:31

28:31 “You are to make the robe ¹  of the ephod completely blue.

[28:31]  ¹ tn The מְעִיל (mÿ’il), according to S. R. Driver (Exodus, 307), is a long robe worn over the ephod, perhaps open down the front, with sleeves. It is made of finer material than ordinary cloaks because it was to be worn by people in positions of rank.