Leviticus 14:8
The Seven Days of Purification
14:8 “The one being cleansed must then wash his clothes, shave off all his hair, and bathe in water, and so be clean. Then afterward he may enter the camp, but he must live outside his tent seven days.
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.
Numbers 19:12
19:12 He must purify himself
with water on the third day and on the seventh day, and so will be clean. But if he does not purify himself on the third day and the seventh day, then he will not be clean.
Ezekiel 43:25-27
43:25 “For seven days you will provide every day a goat for a sin offering; a young bull and a ram from the flock, both without blemish, will be provided.
43:26 For seven days they will make atonement for the altar and cleanse it, so they will consecrate it.
43:27 When the prescribed period is over, on the eighth day and thereafter the priests will offer up on the altar your burnt offerings and your peace offerings; I will accept you, declares the sovereign Lord.”