Exod.30.10

And Aaron shall make an atonement upon the horns of it once in a year with the blood of the sin offering of atonements: once in the year shall he make atonement upon it throughout your generations: it is most holy unto the LORD.

Exod.30.10

Once a year Aaron is to purify the Altar horns. Using the blood of the Absolution-Offering of atonement, he is to make this atonement every year down through the generations. It is most holy to GOD."

Exod.30.10

And Aaron shall make atonement upon its horns once a year with the blood of the sin offering of atonement; once a year he shall make atonement upon it throughout your generations. It is most holy to the LORD."

Exod.30.10

"Once a year Aaron must purify the altar by placing on its horns the blood from the offering made for the atonement of sin. This will be a regular, annual event from generation to generation, for this is the LORD's supremely holy altar."