Leviticus 4:25-26

25Then the priest is to take some of the blood of the sin offering with his finger, put it on the horns of the altar of burnt offering, and pour out the rest of the blood at the base of the altar. 26He must burn all its fat on the altar, like the fat of the peace offerings; thus the priest will make atonement for that man’s sin, and he will be forgiven.