Exodus 28:36-38

36“You shall also make 1a plate of pure gold and shall engrave on it, like the engravings of a seal, ‘2Holy to the Lord.’ 37You shall 3fasten it on a 4blue cord, and it shall be on the turban; it shall be at the front of the turban. 38It shall be on Aaron’s forehead, and Aaron shall 56take away the iniquity of the holy things which the sons of Israel consecrate, with regard to all their holy gifts; and it shall always be on his forehead, that 7they may be accepted before the Lord.