Exodus 30:10
10Once a year, Aaron shall make atonement on the horns [of the altar] with the blood of the sin offering of atonement. Throughout your generations he shall make atonement on it annually. The altar [is] holy to AO.”
10Once a year, Aaron shall make atonement on the horns [of the altar] with the blood of the sin offering of atonement. Throughout your generations he shall make atonement on it annually. The altar [is] holy to AO.”