Leviticus 4:7-8

7The priest will then put some of the blood on the horns of the altar for fragrant incense that stands in the Lord’s presence inside the Tabernacle. He will pour out the rest of the bull’s blood at the base of the altar for burnt offerings at the entrance of the Tabernacle.

8Then the priest must remove all the fat of the bull to be offered as a sin offering. This includes all the fat around the internal organs,