Chullin 93

Hook

At the heart of the laws of kosher meat lies a startling anatomical paradox: a single molecule of fat can shift from being a holy, altar-worthy substance whose consumption carries the ultimate spiritual penalty of karet (excision) to being a perfectly mundane, permissible piece of food, based entirely on whether it sat above or below a thin flap of muscle. In Chullin 93a, the Talmud reveals that the boundaries of the sacred and the profane are not abstract theological lines, but dynamic, moving borders mapped directly onto the shifting joints of a walking beast.

Context

To understand the intense anatomical debates of Chullin 93a, we must step back to the transition from the biblical sacrificial cult to the rabbinic dinner table. In the wilderness tabernacle and the Temples of Jerusalem, certain fats—known as chelev—were designated exclusively for the altar of God. As detailed in Leviticus 3:3-4, these included the fat covering the innards, the fat upon the loins, and the fat upon the kidneys. When the Temple was destroyed in 70 CE, the physical altar ceased to function, but the taboo of the chelev remained absolute. What was once offered to God became strictly forbidden to human beings, under the pain of karet—the spiritual excision of the soul from its people.

This historical shift presented the Sages of the Talmud with a monumental task: how do you translate an ancient, localized sacrificial map into a standardized, reproducible manual of butchery for Jews living across the diaspora, from the banks of the Euphrates in Babylonia to the hills of Galilee in Eretz Yisrael? The challenge was not merely legal, but deeply empirical. The rabbis had to map the words of the Torah onto the complex, wet reality of mammalian anatomy.

This task required a fascinating synthesis of academic legal theory and the somatic, hands-on expertise of professional slaughterers. As we dive into the text, we encounter a world where the highest spiritual realities hang on the scrape of a butcher's knife, the movement of an animal's leg, and the credibility of the working-class craftsmen who prepared the meat.

Text Snapshot

The following passage from Chullin 93a serves as our anchor, showcasing the intricate dialogue between anatomical observation and biblical exegesis:

חֵלֶב שֶׁהַבָּשָׂר חוֹפֶה אוֹתוֹ — מוּתָּר. אַלְמָא ״עַל הַכְּסָלִים״ אָמַר רַחֲמָנָא, וְלֹא שֶׁבְּתוֹךְ הַכְּסָלִים. הָכָא נָמֵי, ״עַל הַכִּלְיוֹת״ אָמַר רַחֲמָנָא, וְלֹא שֶׁבְּתוֹךְ הַכִּלְיוֹת. ... אָמַר אֲבַיֵּי: בְּחַיֶּיהָ אִיפְּרוֹקֵי מִיפָּרְקָא. רַבִּי יוֹחָנָן אָמַר: אֲנָא לָא טַבָּחָא אֲנָא וְלָא בַּר טַבָּחָא אֲנָא, נְהִירְנָא כְּדַהֲוֵינָא בְּבֵי מִדְרְשָׁא אָמְרִי: בְּחַיֶּיהָ אִיפְּרוֹקֵי מִיפָּרְקָא.

“The fat that is covered by the flesh is permitted. Apparently, when the Merciful One states in the Torah that the fat ‘that is upon the loins’ is prohibited, it is referring only to the fat above the loins but not the fat that is inside the loins. Here also, the Merciful One states in the Torah that the fat ‘that is upon the kidneys’ is prohibited, but this does not include the fat that is inside the kidneys... Abaye said: When an animal is alive, its limbs separate at the joints as it walks, [exposing the fat]. Rabbi Yoḥanan said: I am not a butcher, and I am not the son of a butcher, but I remember what they would say in the study hall: When an animal is alive, its limbs separate at the joints as it walks.”

— Chullin 93a:1-2 (Source: Sefaria)

Close Reading

Insight 1: Structural Dynamics of the Living Carcass (Ipruki Mi-prak)

The opening discussion of our passage presents a glaring logical contradiction. On one hand, Shmuel establishes the broad, elegant rule: Chelev she-habashar chofeh oto mutar—"The fat that is covered by the flesh is permitted." This is rooted in a highly literal reading of Leviticus 3:4, which prohibits only the fat that is upon (al) the loins and kidneys. If the fat is buried deep within the muscle tissue, it is categorized as "inside" (b'toch) rather than "upon," and is therefore permitted.

However, the Gemara immediately challenges this rule with an empirical observation: Shmuel himself elsewhere rules that the fat under the loins is strictly forbidden. If this fat is located underneath the loins, it is by definition covered by a thick layer of loin flesh. Why, then, does it not benefit from the leniency of covered fat?

The resolution offered by both Abaye and Rabbi Yoḥanan is brilliant in its biomechanical sensitivity: B’chayei ipruki mi-prak—"When the animal is alive, its limbs separate at the joints as it walks."

This insight shifts our entire understanding of halakhic anatomy. The Talmud is asserting that we do not determine the status of an animal's tissues based solely on the static, cold state of the carcass lying on the butcher's table. Instead, we must evaluate the tissue through the lens of the animal's living history.

When the animal is alive and moving, the act of locomotion causes the muscles and joints of the flank to stretch, slide, and separate. During these moments of movement, the fat beneath the loins is momentarily exposed to the outside world; it is no longer truly "covered" by the flesh. Because this fat is exposed during the animal's life, it loses its status as "covered fat" (chafuy) and retains its biblical prohibition as fat "upon the loins."

This dynamic view of anatomy teaches us a profound lesson about the halakhic worldview. The physical status of an object is not merely a snapshot of its current, passive state. It is deeply connected to its active, functional reality. The carcass on the table is legally defined by the ghost of its living movement.

Insight 2: Key Term Analysis — The Anatomy of Chafuy (Covered)

To fully appreciate this sugya, we must analyze the precise linguistic and physical boundaries of what the Talmud calls chafuy (covered). What constitutes a valid "covering" of flesh?

Let us turn to Rashi's commentary on this page, which provides a masterclass in medieval anatomical observation. Rashi explains:

חלב שהבשר חופה אותו - חלב שעל הכסלים שתחת הכליות ונראה בגובה הכסלים ואח"כ נבלע תחת הבשר אדום דק ומתפשט תחת אותו בשר בכל הכסלים ומשהבשר חופהו מותר...

"The fat that the flesh covers: This is the fat upon the flanks (loins) that is under the kidneys, which is visible at the height of the flanks, and then is swallowed under the thin red flesh and spreads under that flesh throughout the flanks. And from the moment the flesh covers it, it is permitted..."

— Rashi on Chullin 93a:1:1

Notice how Rashi carefully traces the physical journey of the fat. It starts out visible and exposed at the "height of the flanks," but then it is "swallowed" (nivla) beneath a layer of "thin red flesh" (basar adom dak).

Rashi's use of the term flancs (translated in the Otzar La'azei Rashi as "loins, flanks, the inner muscles of the thigh next to the kidney") anchors this discussion in actual mammalian dissection. The "thin red flesh" Rashi refers to is the abdominal wall musculature (such as the transversus abdominis or obliquus internus), which overlays the deeper retroperitoneal fat deposits.

But Rashi doesn't stop there. He notes a major halakhic dispute regarding the end of this muscle layer:

וכשכלה למטה אותו בשר יוצא ממנו קרום עב ולבן לבד קרום דק וקלוש המתפשט בכל הכסלים שאסור משום חלב כדלקמן ותחת אותו קרום עב יש חלב ויש שנוהגים איסור באותו חלב לפי שאותו קרום אינו חשוב חפוי בשר... אבל בארץ אשכנז נוהגין בו היתר וגם בעיני נראה דחפוי גמור הוא.

"And when that flesh terminates below, there emerges from it a thick white membrane—distinct from the thin, frail membrane that spreads across all the flanks, which is forbidden as chelev... and beneath that thick membrane, there is fat. And there are those who practice a prohibition regarding that fat, because they hold that this membrane is not considered a true 'covering of flesh'... But in the land of Ashkenaz, they practice permission regarding it, and also in my eyes it appears to be a complete covering."

— Rashi on Chullin 93a:1:1

This passage reveals a fascinating debate over the material definition of "flesh" (basar). Is a thick, fibrous aponeurosis or tendon (the "thick white membrane" that emerges where the red muscle ends) considered "flesh" for the purpose of covering the fat?

• The stringent view argues that only "red flesh" (muscle tissue) can act as a halakhic shield to permit underlying fat. A membrane, even a thick one, is too structurally distinct from meat to count as a covering.
• Rashi, defending the custom of Ashkenaz, argues for a functional definition of covering. If the membrane is thick, tough, and completely seals the fat away, it performs the exact same protective, enclosing function as muscle tissue. Therefore, it qualifies as chafuy and the fat beneath it is permitted.

This debate shows that the Sages and commentators were not merely applying abstract rules; they were engaged in incredibly detailed, tactile examinations of animal carcasses, arguing over the halakhic translation of membranes, fascia, and muscle bodies.

Insight 3: The Epistemological Tension — Academic Authority vs. Trade Expertise

One of the most human and dramatic moments in the entire tractate occurs when Rabbi Yoḥanan, the undisputed leader of the Torah academies of Eretz Yisrael, makes a surprising confession:

אָמַר רַבִּי יוֹחָנָן: אֲנָא לָא טַבָּחָא אֲנָא וְלָא בַּר טַבָּחָא אֲנָא...

"Rabbi Yoḥanan said: I am not a butcher, and I am not the son of a butcher..."

— Chullin 93a:2

Why does Rabbi Yoḥanan feel compelled to state this? In the ancient world, butchery was a highly specialized, hereditary trade. A master butcher (tabach) possessed deep, non-verbal, tactile knowledge of animal anatomy. They knew exactly where the joints separated, where the hidden veins ran, and how to slice through muscle to expose the forbidden fats without puncturing the organs. This was guild-knowledge, passed down from father to son through years of physical apprenticeship.

Rabbi Yoḥanan is acknowledging a profound epistemological gap. He, as a scholar of the Beit Midrash (study hall), does not possess this native, somatic expertise. He cannot claim authority based on personal trade experience. Yet, he asserts that the collective memory of the Beit Midrash—which preserves the traditions of empirical observation—aligns perfectly with the practical reality of the slaughterhouse: "but I remember what they would say in the study hall: When an animal is alive, its limbs separate at the joints."

This tension between academic rabbinic authority and the empirical knowledge of tradesmen runs throughout the rest of the page, particularly in the discussion of whether butchers are trusted (ne'emanim) to testify that they have properly removed the forbidden fats (chelev) and the sciatic nerve (gid ha-nasheh).

The Talmud notes a historical shift in this trust. Initially, when the Sages followed the stringent opinion of Rabbi Meir—who required butchers to meticulously scrape away every tiny root and branch of the sciatic nerve—the butchers were deemed untrustworthy. Why? Because the work was simply too exhausting and labor-intensive (tircha). The Sages feared that a tired butcher, working under financial pressure, would take shortcuts and leave forbidden tissue behind.

However, when the halakha shifted to follow Rabbi Yehuda—who ruled that only the main branches of the nerve must be removed, a far less arduous task—the butchers were once again deemed trustworthy. Their reliability was not a static moral quality; it was a function of the physical difficulty of their labor.

Later, the Gemara records an even more subtle psychological twist:

כֹּל הֵיכָא דִּדְכִירִי לֵיהּ לִדְרַבִּי יְהוּדָה — לָא מְהֵימְנִי, וְהָאִידָּנָא דְּאַנְשְׁיֻהּ לִדְרַבִּי יְהוּדָה וְנָהוּג כְּרַבִּי מֵאִיר — מְהֵימְנִי.

"As long as they remembered the opinion of Rabbi Yehuda [and did not scrape], they were not trusted [if they claimed to have scraped]. But now that they have forgotten the opinion of Rabbi Yehuda and have grown accustomed to scraping... they are trusted."

— Chullin 93a:24

Once the stringent practice of scraping became the default, habitual norm of the trade, the physical effort ceased to be an extraordinary burden. It became "second nature" to the butchers. Because they no longer perceived the scraping as an exhausting extra task, the psychological temptation to cheat vanished.

This is a breathtaking sociological insight. The halakha recognizes that human integrity is deeply intertwined with habit, physical exertion, and professional culture. The Beit Midrash does not rule from an ivory tower; it must constantly calibrate its laws to the physical and psychological realities of the slaughterhouse floor.

Two Angles

To see how these principles translate into concrete legal rulings, let us contrast the two classic approaches of the medieval commentators regarding the loben koliya—the white fat that penetrates into the interior of the kidney.

The Talmudic text records a fundamental dispute:

לֹבֶן כּוּלְיָא — רַב וְרַבִּי חִיָּא, חַד אָסַר וְחַד שָׁרֵי.

"The white fat of the kidney: Rav and Rabbi Ḥiyya disagreed. One prohibits it, and one permits it."

— Chullin 92b:8

How do we rule in the face of this absolute disagreement?

Angle 1: The Stringent School (Rashi and the Ba'al HaTrumot)

Rashi, representing the classic Ashkenazic approach, leans toward stringency in this matter. He notes that the Talmud never explicitly resolves the dispute between Rav and Rabbi Ḥiyya in a definitive halakhic statement. Furthermore, when analyzing the practical behavior of the later Amoraic sages, we see that Rava and Rabbi Yoḥanan would "scrape" (mêmartit) the white fat off, removing it entirely.

Rashi writes:

ובלובן כוליא הלך אחר המחמיר לשרש אחריו כיון דלא איתוקם הלכתא כרבי אסי והמחמיר יחמיר והמונע לא הפסיד:

"And regarding the white of the kidney, follow the stringent view to root it out completely, since the halakha was not established like Rabbi Assi [who only trimmed it]. And the one who is stringent should be stringent, and the one who abstains loses nothing."

— Rashi on Chullin 93a:1:1

For Rashi, when dealing with a potential biblical prohibition carrying the penalty of karet, we must adopt a posture of absolute caution. If the great sages of the Talmud went to the effort of scraping this fat away, it indicates that we cannot rely on the leniency of "covered fat" when it comes to the complex interior of the kidney.

Angle 2: The Lenient/Systemic School (Rif, Rambam, and Rashba)

In sharp contrast, the great Sephardic codifiers—the Rif Rif Chullin 30b:1 and Maimonides (Hilkhot Ma'akhalot Assurot 7:7)—rule that the white fat inside the kidney is fundamentally permitted.

Their argument, masterfully unpacked by the Rashba, is built on a systemic reading of the talmudic sugya. They point out that Abaye explicitly states: "The logical reasoning aligns with Rabbi Assi [who only trimmed the surface fat], because Shmuel said: 'The fat that the flesh covers is permitted.'"

The Rashba defends this lenient ruling with a profound textual analysis:

ומיהו קיימא לן כשמואל דאמר חלב שהבשר חופה אותו מותר, דהא ליכא מאן דפליג עלה... ואם תאמר אם כן מאי קא מייתי מדשמואל דהא אף רבה ור' יוחנן מודה בה מדאורייתא מישרא שרי ליה, יש לומר משום דפליגי בה רבי ורבי חייא דחד מינייהו אסר אמר אביי דמדאורייתא שרי מדשמואל... מותר לגמרי קאמר, ואפילו מצות פרוש אין בו...

"However, we establish the law like Shmuel, who said that fat covered by flesh is permitted, for there is no one who disputes this... and if you ask: if so, why does Abaye bring proof from Shmuel, when even Rava and Rabbi Yoḥanan agree that biblically it is permitted? One can say: because Rabbi and Rabbi Ḥiyya argued, and one of them prohibited it, Abaye came to teach that biblically it is permitted based on Shmuel... meaning it is completely permitted, and there is not even a pious duty to abstain from it..."

— Rashba on Chullin 92b:8

The Rashba's reading is incredibly bold. He argues that because the Torah specifically uses the language "upon the kidneys" Leviticus 3:4, it intentionally excludes anything inside the kidney. This is an absolute biblical exclusion.

Therefore, the actions of Rava and Rabbi Yoḥanan—who scraped the fat out—were not practicing a formal prohibition. Rather, they were adopting a personal "measure of piety" (midat chasidut).

For the general public, however, there is absolutely no obligation to go beyond the letter of the law. The fat inside the kidney is treated as simple meat, and the halakha follows Rabbi Assi, who merely trimmed the visible fat on the outside without digging into the kidney's interior recesses.

Feature	Angle 1: Stringent School (Rashi)	Angle 2: Lenient School (Rif / Rambam / Rashba)
Primary Source	Rashi on Chullin 93a:1:1	Rashba on Chullin 92b:8, Rif Rif Chullin 30b:1
Halakhic Status	Forbidden (requires deep scraping)	Permitted (requires only surface trimming)
Core Argument	The Talmud leaves the dispute unresolved; Rava & Rabbi Yoḥanan scraped it, so we must be stringent.	Abaye explicitly aligns the law with the lenient view using Shmuel's rule of covered fat.
View of Sage's Stringency	Reflects a binding or highly recommended legal standard.	Reflects a personal "measure of piety" (midat chasidut), not a general law.

Practice Implication

This entire talmudic discussion is not a relic of the past; it directly shapes the physical reality of the global kosher meat industry today through the practice of Nikur (porging/deveining).

Because the Torah prohibits the sciatic nerve (gid ha-nasheh) and various chelev fats located in the hindquarters of the animal, these forbidden tissues must be meticulously extracted before the meat can be eaten by Jews. This process is incredibly complex, requiring deep anatomical knowledge of the animal's circulatory and muscular systems.

In the modern era, this talmudic page has created a fascinating geographic and cultural divide:

The Ashkenazic Custom (No Hindquarter Meat)

In almost all Ashkenazic communities in the Western world (such as the US, UK, and Europe), the art of Nikur on the hindquarters has been completely abandoned. Because the process is so incredibly labor-intensive, and because the risk of a butcher missing a microscopic piece of forbidden fat is so high, major kosher certification agencies (such as the OU, OK, and Star-K) decided that it was economically and halakhically unfeasible to supervise.

Consequently, in Ashkenazic slaughterhouses, the animal is cut in half at the 12th rib. The front half (forequarters) is processed and sold as kosher, while the entire back half (containing the sirloin, tenderloin, flank steak, and filet mignon) is sold off to the non-kosher market. This is why you will rarely find a kosher filet mignon in a standard American kosher butcher shop.

The Sephardic Custom (Active Nikur)

In contrast, many Sephardic communities, particularly in Israel, Turkey, and North Africa, have continuously preserved the oral, tactile tradition of hindquarter Nikur. Master menakrim (porgers) undergo years of rigorous apprenticeship to map the exact pathways of the veins and fats discussed in Chullin 93a. In these communities, you can walk into a kosher butcher shop and purchase hindquarter cuts, because they rely on the living chain of trade expertise that Rabbi Yoḥanan honored in his famous statement.

This shows that a single page of the Talmud directly dictates the economics of the global meat market, the training of kosher supervisors, and the very cuts of meat that appear on Jewish dinner tables Friday night.

Chevruta Mini

Now it's your turn to step into the Beit Midrash. Grab a partner, read through these two questions, and debate the underlying conceptual tradeoffs:

1. The Nature of Anatomy: When the Talmud rules that fat is forbidden because "when the animal walks, its joints separate and expose the fat," it is defining a dead carcass by its living movements.

   • The Question: Is Halakha defining the physical world as a static material reality (what is in front of us right now) or as a dynamic, historical process (how this object functioned in life)? What are the philosophical implications of a law that looks at a piece of meat and sees the phantom movement of a living cow?

2. The Psychology of Trust: The Talmud suggests that we cannot trust a butcher if the job is too physically demanding, but we can trust him if the job is easy, or if the hard job has become a deeply ingrained professional habit.

   • The Question: In modern spiritual life, do we find greater reliability in conscious, hard-won effort or in thoughtless, habitual routine? If a religious practice becomes too easy or automated through technology, does that increase our spiritual integrity, or does it detach us from the necessary mindfulness of the commandment?

Takeaway

The laws of kosher meat reveal that the boundary between the sacred and the profane is mapped not by abstract theology, but by the kinetic movement of a living muscle and the meticulous, trusted hand of a working craftsman.