Exodus 29:9

29:9 and wrap the sashes around Aaron and his sons and put headbands on them, and so the ministry of priesthood will belong to them by a perpetual ordinance. Thus you are to consecrate Aaron and his sons.

Exodus 29:35

29:35 “Thus you are to do for Aaron and for his sons, according to all that I have commanded you; you are to consecrate them for seven days.