Exodus 29:9

Wrap the sashes around Aaron and his sons and tie headbands on them. The priesthood shall be theirs by a permanent statute. In this way you are to ordain Aaron and his sons.

And thou shalt gird them with girdles, Aaron and his sons, and put the bonnets on them: and the priest’s office shall be theirs for a perpetual statute: and thou shalt consecrate Aaron and his sons.