Leviticus 3:9-11

And of the peace-offering, let him give an offering made by fire to the Lord; the fat of it, all the fat tail, he is to take away near the backbone; and the fat covering the inside parts and all the fat on the inside parts, And the two kidneys, with the fat on them, which is by the top part of the legs, and the fat joining the liver and the kidneys, he is to take away; That it may be burned by the priest on the altar; it is the food of the offering made by fire to the Lord.