Leviticus 7:4

And he shall bring one of all his gifts, a separate offering to the Lord: it shall belong to the priest who pours forth the blood of the peace-offering.

And the two kidneys, and the fat that is on them, which is by the flanks, and the caul that is above the liver, with the kidneys, it shall he take away:

and he shall take away the two kidneys, and the fat that is on them, which is by the loins, and the cover on the liver, with the kidneys;