Ezekiel 43:25-27

Seven 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. Seven days shall they make atonement for the altar and purify it; so shall they consecrate it. And 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 Jehovah.