John Gill Commentary Leviticus 4:31

"And all the fat thereof shall he take away, as the fat is taken away from off the sacrifice of peace-offerings; and the priest shall burn it upon the altar for a sweet savor unto Jehovah; and the priest shall make atonement for him, and he shall be forgiven." — Leviticus 4:31 (ASV)

(See Gill on Leviticus 4:30).