Exodus 28:36-38 - The Turban
36 Also make a plate of pure gold and engrave on it, like the engravings of a seal: Holy to Jehovah.
37 Fasten it on a blue cord and on the turban. It should be at the front of the turban. 38 It shall be on Aaron's forehead. Aaron will take away the iniquity of the holy things that the sons of Israel consecrate. Concerning their holy gifts it will always be on his forehead that they may be accepted before Jehovah.