Exodus 29:30

29:30 The priest who succeeds him from his sons, when he first comes to the tent of meeting to minister in the Holy Place, is to wear them for seven days.

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.

Exodus 29:37

29:37 For seven days you are to make atonement for the altar and set it apart as holy. Then the altar will be most holy. Anything that touches the altar will be holy.