ויקרא, פרק ג׳, פסוק ד׳

The peace offering involves a precise selection of internal organs and fats designated to be burned on the altar. Central to this process are the kidneys. The requirement to take exactly two kidneys establishes an important standard: an animal born with an internal defect, such as having only one kidney or possessing three, is unfit for the altar [תורה תמימה, מלבי״ם, אדרת אליהו]. Conceptually, the kidneys hold deep significance, as they are viewed as the physical center of human longing, lust, and inner counsel [אבן עזרא, ביאור יש״ר].

The removal of the fat is highly specific, targeting only the outer layer wrapping the kidneys while excluding the white threads found inside the organ itself [מלבי״ם]. This fat extends upward to the flanks of the animal. While there is a general rule that animal fat covered by flesh is permitted for consumption, this specific fat remains strictly forbidden. As the living animal walks, its natural movement causes this fat to be intermittently exposed, meaning it is not truly considered covered [רש״י, תורה תמימה, מלבי״ם]. The flanks themselves carry symbolic weight, representing trust and hope, as physical illness in this region naturally triggers deep human anxiety and worry [ביאור יש״ר].

Another key element of the offering involves a specific internal appendage. The primary approach among commentators is that this refers to the diaphragm, the membrane separating the respiratory and digestive systems [רש״י, מזרחי, תורה תמימה, מלבי״ם, שפתי חכמים]. Alternatively, some identify it not as a separate membrane, but as an extra, finger-like lobe protruding directly from the liver [רשב״ם, רלב״ג, רד״צ הופמן]. The instruction to take this part alongside the liver does not mean the entire liver is offered. Rather, the appendage is cut away together with a small, attached piece of the liver itself [רש״י, מזרחי, גור אריה, הכתב והקבלה, דברי דוד, אבן עזרא, ביאור יש״ר, מלבי״ם].

The removal of this appendage is performed as an action entirely separate from, and in addition to, the removal of the kidneys [רש״י, הכתב והקבלה, שטיינזלץ, משכיל לדוד]. This highlights the independence of each step in the offering process. The successful removal of one organ does not depend on the presence of the other. If the kidneys are lost or missing, the appendage must still be removed and offered, just as the kidneys would be offered even if the appendage were missing [תורה תמימה, אדרת אליהו, הכתב והקבלה].