Exodus 29:6-9

Put the turban on his head, and put the holy crown on the turban. Take the special olive oil and pour it on his head to make him a priest. “Then bring his sons and put the inner robes on them. Put the headbands on their heads, and tie cloth belts around their waists. Aaron and his descendants will be priests in Israel, according to a rule that will continue from now on. This is how you will appoint Aaron and his sons as priests.