Ezekiel 43:26 in the King James Version
Seven days shall they purge the altar and purify it; and they shall consecrate themselves.
Context
25 “Seven days you shall prepare every day a goat for a sin offering. They shall also prepare a young bull and a ram out of the flock, without defect.
26 Seven days shall they make atonement for the altar and purify it. So shall they consecrate it.
27 When they have accomplished the days, it shall be that on the eighth day and onward, the priests shall make your burnt offerings on the altar and your peace offerings. Then I will accept you,’ says the Lord GOD.”