Exodus 28:33-35

33And upon its hem you shall make pomegranates of blue, purple, and scarlet, all around its hem, and bells of gold between them all around:

34a golden bell and a pomegranate, a golden bell and a pomegranate, upon the hem of the robe all around.

35And it shall be upon Aaron when he ministers, and its sound will be heard when he goes into the holy place before the Lord and when he comes out, that he may not die.