Exodus 28:41-43

New Century Version

⁴¹ Put these clothes on your brother Aaron and his sons, and pour olive oil on their heads to appoint them as priests. Make them belong to me so they may serve me as priests.

⁴² “Make for them linen underclothes to cover them from the waist to the upper parts of the legs. ⁴³ Aaron and his sons must wear these underclothes when they enter the Meeting Tent and anytime they come near the altar to serve as priests in the Holy Place. If they do not wear these clothes, they will be guilty of wrong, and they will die. This will be a law that will last from now on for Aaron and all his descendants.