Exodus 28:31-35

“And you shall make the robe of the ephod all of blue. There shall be an opening at its top in the center [for the head], with a binding of woven work around the opening, like the opening in a coat of armor, so that it will not tear or fray. You shall make pomegranates of blue, purple, and scarlet fabric all around its hem, with gold bells between them; a golden bell and a pomegranate, a golden bell and a pomegranate, all around the [bottom] hem of the robe. Aaron shall wear the robe when he ministers, and its sound shall be heard when he goes [alone] into the Holy Place before the LORD, and when he comes out, so that he will not die there.