Exodus 28:33-35

On its hem you shall make pomegranates of blue and purple and scarlet yarns, around its hem, with bells of gold between them, a golden bell and a pomegranate, a golden bell and a pomegranate, around the hem of the robe. And it shall be on Aaron when he ministers, and its sound shall be heard when he goes into the Holy Place before the LORD, and when he comes out, so that he does not die.