Exodus 28:40-43

⁴⁰Make inner robes, belts and caps for Aaron’s sons. When they are wearing them, people will honor his sons. They will also have respect for them. ⁴¹Put all these clothes on your brother Aaron and his sons. Then pour olive oil on them and prepare them to serve me. Set them apart to serve me as priests. ⁴²“Make linen underwear that reaches from the waist to the thigh. ⁴³Aaron and the priests in his family line must wear it when they enter the tent of meeting. They must also wear it when they approach the altar to serve in the Holy Room. Then they will not be found guilty and die. “For all time to come, that will be a law for Aaron and the priests in his family line.