Exodus 28:40-43

CLV(i) 40 Also you shall make tunics for the sons of Aaron. Then you will make sashes for them, and you shall make caps for them, for glory and for beauty. 41 You will put them on Aaron, your brother, and his sons with him, and you will anoint them. You will fill their hands and hallow them, and they will serve as priests for Me. 42 Make for them linen breeches to cover the maked flesh. From the waists and unto the thighs shall they come to be; 43 and they will come to be on Aaron and on his sons when they enter into the tent of appointment or when they come close to the altar to minister in the holy place, so that they may not bear depravity, and should die. It is an eonian statute for him and for his seed after him.