Leviticus 3:3-5

3The person must burn some pieces of the animal as a gift to the Lord. It is a friendship offering.

4He must bring all the fat from inside the animal. And he must bring the kidneys with their fat and the best piece of the liver.

5The priests, Aaron's sons, will take the pieces. They must put them on top of the gift on the altar. The smell of them while they are burning will give the Lord pleasure.