Leviticus 4:9

4:8 He shall take from it all the fat of the bull as the sin offering. The fat that covers the entrails and all the fat which is on the entrails,

4:9 the two kidneys and the fat that is on them by the flanks, and the fatty lobe attached to the liver above the kidneys, he shall remove,

4:10 as it was taken from the bull of the sacrifice of the peace offering; and the priest shall burn them on the altar of the burnt offering.