Exodus 29:6-9

and you shall put the turban on his head and put the holy crown on the turban. Then you shall take the anointing oil and pour it on his head and anoint him. You shall bring his sons and put tunics on them. And you shall wrap them with sashes, Aaron and his sons, and put the [ornamental] caps on them; and the priest’s office shall be theirs by a perpetual statute. So you shall ordain Aaron and his sons.