Ezekiel 43:25-27

25Seven days shalt thou prepare every day a goat for a sin offering: they shall also prepare a young bullock, and a ram out of the flock, without blemish. 26Seven days shall they make atonement for the altar and purify it; so shall they consecrate it. 27And when they have accomplished the days, it shall be that upon the eighth day, and forward, the priests shall make your burnt offerings upon the altar, and your peace offerings; and I will accept you, saith the Lord GOD.