Exodus 28:36-38

³⁶"And you shall make a plate of pure gold, and engrave on it, like the engraving of a signet, `Holy to the LORD.' ³⁷And you shall fasten it on the turban by a lace of blue; it shall be on the front of the turban. ³⁸It shall be upon Aaron's forehead, and Aaron shall take upon himself any guilt incurred in the holy offering which the people of Israel hallow as their holy gifts; it shall always be upon his forehead, that they may be accepted before the LORD.