Exodus 28:31

31. "Make the robe of the ephod entirely of blue cloth,
32. with an opening for Aaron's head in the middle of it. The opening will be reinforced by a woven collar so it will not tear.
33. Make pomegranates out of blue, purple, and scarlet yarn, and attach them to the hem of the robe, with gold bells between them.
34. The gold bells and pomegranates are to alternate all the way around the hem.
35. Aaron will wear this robe whenever he enters the Holy Place to minister to the LORD, and the bells will tinkle as he goes in and out of the LORD's presence. If he wears it, he will not die.