Exodus 28:37-41

You shall fasten it on a violet cord, and it shall be on the turban; it shall be at the front of the turban.

It shall be on Aaron’s forehead, and Aaron shall take away the guilt of the holy things which the sons of Israel consecrate, regarding all their holy gifts; and it shall always be on his forehead, so that they may be accepted before the Lord.

“And you shall weave the tunic of checkered work of fine linen, and shall make a turban of fine linen, and you shall make a sash, the work of a weaver.

“For Aaron’s sons you shall also make tunics; you shall also make sashes for them, and you shall make caps for them, for glory and for beauty.

Then you shall put them on Aaron your brother and on his sons with him; and you shall anoint them and ordain them and consecrate them, so that they may serve Me as priests.