Rashi on Leviticus 4:31/רש"י על ויקרא ד׳:ל״א

1כאשר הוסר הלב מעל זבח השלמים [AND HE SHALL REMOVE ALL THE FAT] AS THE FAT IS REMOVED FROM OFF THE SACRIFICE OF PEACE OFFERINGS — i.e. as the fat portions of the goat which are mentioned in the case of peace offerings (cf. previous verse).