Now, remember that the blood of the typical sin offering was placed on the horns of the altar. Because of what the blood represented, it is as though the horns of the golden altar became a repository for the sins of the priests and the congregation (see Leviticus 4:7, 18). The prophet Jeremiah describes all the accumulated blood and sin:
This describes just how sinful Judah was, and God says it is like the sins are engraved on the horns of the altars. With each sin offering, another record of guilt was added to the horns. The word engraved indicates a great deal of repetition. That's a lot of sin offerings. God's prescription was an annual cleansing of the golden altar, and specifically the horns, where the defiled blood was put. But the high priest had to use blood from an animal that did not have sins transferred to it. A typical sin offering would just add more sin to the altar. Instead, undefiled blood was needed. Once a year, then, the special sin offering of atonements was made to cleanse the horns of the golden altar.
