Leviticus 4:20, 26, 35

He shall also do with the bull just as he did with the bull of the sin offering; that is what he shall do with this. So the priest shall make atonement for [the sin of] the people, and they will be forgiven.

And he shall offer all its fat up in smoke on the altar like the fat from the sacrifice of peace offerings; so the priest shall make atonement for him in regard to his sin, and he will be forgiven.

Then he shall remove all its fat, just as the fat of the lamb is removed from the sacrifice of the peace offerings, and the priest shall offer it up in smoke on the altar, on the offerings by fire to the LORD. In this way the priest shall make atonement for him in regard to the sin which he has committed, and he will be forgiven. [Heb 9:13, 14]