10 And Aaron shall pray on the horns thereof once by the year, in the blood which is offered for sin, and he shall please (the Lord) thereon in your generations; it shall be the holy of holy things to the Lord. (And once every year Aaron shall put blood on its horns, from the yearly sin offering, and for all your generations to come, the priest shall cleanse, or shall purify, the altar in this way; for it is most holy to the Lord.)