Leviticus 7:4-6

⁴And the two kidneys, and the fat that is on them, which is on the flanks, and the midriff above the liver, with the kidneys shall he remove the same:

⁵And the priest shall burn them upon the altar for an offering made by fire unto the Lord; it is a trespass-offering.

⁶Every male among the priests may eat thereof; in a holy place shall it be eaten: it is most holy.