Priests: Ceremonies at Consecration of Lasted Seven Days
Source: TTT
Exodus 29:35–37
This is what you are to do for Aaron and his sons based on all that I have commanded you, taking seven days to ordain them. / Sacrifice a bull as a sin offering each day for atonement. Purify the altar by making atonement for it, and anoint it to consecrate it. / For seven days you shall make atonement for the altar and consecrate it. Then the altar will become most holy; whatever touches the altar will be holy.
Leviticus 8:33
You must not go outside the entrance to the Tent of Meeting for seven days, until the days of your ordination are complete; for it will take seven days to ordain you.