Commentaire sur Le Lévitique 3:4

הכסלים — Flancs in O. F. — It speaks of the fat which is on (על) the kidneys being also on (על) the flanks because the fat that is upon the kidneys is, when the animal is living, on the uppermost part of the flanks, and they (the kidneys) are in a downward position. This is the fat which is under the loins — what are called lombles in O. F.; it is that white fat which is visible upon the upper part of the flanks, but on their lower part the flesh covers it, (and this latter portion of the fat is therefore not upon but under the flanks).

היותרת, a growth on top of the liver.

Separating. The separation (the diaphragm) which divides between the respiratory organs and the intestines is called in the Talmud “the lobe of the liver.”

היותרת is the protecting wall (membrane) over the liver which is called abris in O. F. In the Aramaic language it is called חצרא דכבדא the lobe of the liver.

The liver. Accordingly, the word על means “with a little of the liver.” We should not say [he removes] the entire liver, for if so, it should say “he shall remove them.”

על הכבד — This must mean that he shall take a little of the liver with it, for in another place it distinctly states, (Leviticus 9:10) “and the יותרת מן הכבד [he caused to ascend in fumes]” (Sifra, Vayikra Dibbura d'Nedavah, Section 14 8).

And in another place. I.e. this is proof that “on the liver” means [he should take a little] of the liver [with it].

על הכבד על הכליות — means, besides the part of the liver and besides the kidneys shall he remove this (the יותרת‎).

Aside. Re”m raises a difficulty: Above, Rashi explains “על” means “with” and here he explains that “על” means “aside.” The answer is: The word על has two explanations, “with” and “aside.” Concerning the kidneys Rashi perforce explains that על means “aside from the kidneys,” because the entire kidneys are burnt on the altar. However, here when he explains that “על הכבד” means “aside from the liver,” he is not saying that the word על appearing in conjunction with “liver” means “aside from.” Rather, he is eliminating an error that we might say the kohein burns on the altar only that area of the lobe of the liver which is attached to a small part of the liver, [but not the entire lobe]. Therefore, he explains “aside from the liver,” i.e., the entire lobe was burnt with that little that was attached to the liver (Minchas Yehudah). It appears that Rashi’s intention is clear and proper [unlike Re”m contends]. At first, Rashi writes that the fact that Scripture equates the liver and the kidneys was certainly not with regard to burning on the altar, because the liver is not burnt. If so, you might think that not even a little of the liver is burnt on the altar — but this cannot be. This is because we find different expressions regarding the liver: Here it says: “on the liver,” and in another place it says (9:10): “from the liver.” Thus, it must be that it teaches that the liver is burnt as well, and perforce this means a part of it. Then, Rashi is answering the question: Since it is written: “On the liver on the kidneys,” this implies that they are completely equal, but you maintain that only a part of the liver is burnt whereas the entire kidneys are burnt? To answer this Rashi writes: “[That is,] aside from the liver and aside from the kidneys — he should remove this.” Meaning: With regard to removing [the lobe] they are both equal — the lobe needs to be removed from the liver and the kidneys, each one according to its law — this one in part and this one entirely. Therefore, Rashi concludes “he should remove this,” i.e., in this aspect the liver is the same as the kidneys [but not for burning on the altar] (Divrei Dovid).