Exodus 28:42-43

Good News Translation

⁴² Make linen shorts for them, reaching from the waist to the thighs, so that they will not expose themselves. ⁴³ Aaron and his sons must always wear them when they go into the Tent of my presence or approach the altar to serve as priests in the Holy Place, so that they will not be killed for exposing themselves. This is a permanent rule for Aaron and his descendants.