שמות, פרק כ״ט, פסוק י״ג

Offering the internal parts of an animal upon the altar represents the elevation of the most physical, base elements of life into a spiritual tribute. During the special inauguration period of the priesthood, this particular offering carried unique rules compared to the sacrifices of future generations, which accounts for its slightly abbreviated instructions [העמק דבר].

The process begins with the internal organs [ביאור שטיינזלץ], specifically the distinct layers of fat that can be peeled away, rather than the fat naturally marbled within the meat [ביאור יש"ר]. The primary approach among commentators is that this refers to the membrane enveloping the stomach. There is a nuance regarding the instruction to take the entirety of this fat. [רמב״ן] understands this as a directive to include two distinct types of fat, namely the stomach membrane and the thick fat resting on the intestines. Alternatively, this emphasis ensures that the membrane is removed completely, as it wraps around the stomach like a garment [מזרחי], or it simply serves to include the intestinal fat [גור אריה, דברי דוד].

Next is the diaphragm, the stretched membrane separating the respiratory organs from the digestive tract. Its Hebrew name is rooted in the word for a bowstring, reflecting its taut, sloped structure filled with tendons and veins that facilitate breathing [הכתב והקבלה]. This membrane is not removed in isolation, nor is the entire liver taken. Instead, the diaphragm must be cut and removed alongside a small piece of the liver itself [רש"י, שפתי חכמים, משכיל לדוד].

The two kidneys and their surrounding fat are then prepared. Notably absent from this process is the animal's tail, which is offered in certain other sacrifices. Because this specific offering is a bull, the tail is excluded, as that practice does not apply to bulls or goats [אבן עזרא, ביאור יש"ר]. Conceptually, the kidneys are viewed as the center of human passions, sharing a linguistic root with the concept of deep longing and desire [אבן עזרא].

Finally, these parts are burned on the altar until they turn to smoke [ביאור שטיינזלץ]. This action is consistently described as a process of elevation [נתינה לגר]. The organs are not placed gently upon the altar but are thrown directly into the fire [רש"ר הירש]. This entire sequence carries profound symbolic weight. By surrendering the fat, which represents the pursuit of wealth and materialism, the diaphragm, symbolizing the power and mechanism driving life, and the kidneys, the seat of basic desires, a person transforms their most physical and instinctual traits into free, moral actions that are entirely dedicated to God [רש"ר הירש].