Exodus 28:36-38

³⁶And thou shalt make a plate of pure gold, and grave upon it, like the engravings of a signet, HOLINESS TO THE LORD. ³⁷And thou shalt put it on a blue lace, that it may be upon the mitre; upon the forefront of the mitre it shall be. ³⁸And it shall be upon Aaron's forehead, that Aaron may bear the iniquity of the holy things, which the children of Israel shall hallow in all their holy gifts; and it shall be always upon his forehead, that they may be accepted before the LORD.