Leviticus 8:33-36

33You must stay at the door of the Tent of Meeting for seven days. This will make you holy. You must stay for seven days to become holy.

34The Lord said that you must do this to atone for your sin.

35Remember that you must stay at the door of the Tent of Meeting. You must stay there for seven days and seven nights. The Lord told me that you must do this. If you do not obey him, you will die.’

36So Aaron and his sons did everything that the Lord had told Moses.