Exodus 29:6-9

You shall put the turban on his head, and put the holy crown on the turban. And you shall take the anointing oil, pour it on his head, and anoint him. Then you shall bring his sons and put tunics on them. And you shall gird them with sashes, Aaron and his sons, and put the hats on them. The priesthood shall be theirs for a perpetual statute. So you shall consecrate Aaron and his sons.