Why Are Babylonian Birds Fat? Eretz Yisrael Amoraim Probe the Seemingly Superior Babylonia (Shabbat 145b)

Questioning the Birds, Holidays, and Scholars of Babylonia

This sugya opens with an informal conversation between two rabbis of Eretz Yisrael, R' Ḥiyya bar Abba and R' Asi, while their teacher, R' Yoḥanan, dozes nearby. The questions center on Babylonian Jews and their environment: why are their birds fatter, their holidays more festive, their scholars more ostentatious? And why are non-Jews (spiritually) polluted?

R' Asi answers with sociological explanations: the birds are plump because the environment is favorable (but better ones are found in Gaza wilderness); their holidays are joyous because poverty limits festivity to those days; their scholars dress distinctively because they lack Torah knowledge and need clothing to gain respect; non-Jews are (spiritually) polluted due to their diet of impure creatures.

R' Yoḥanan wakes up and sharply criticizes them for speculative answers not grounded in certainty, quoting Proverbs: only speak what is as clear as the incest prohibitions. He then offers scriptural, theological, and metaphysical alternatives. Babylonian fowl are fat because they were never exiled (Jeremiah 48:11). Judean animals, unlike them, were driven away during 52 years of desolation (Jeremiah 9:9). Mackerels failed to return from Babylonia to Eretz Yisrael due to their frailty, reinforcing the idea of exile affecting even animals.

On holidays, R' Yoḥanan says the Babylonians escaped prophetic curses (Hosea 2:13; Isaiah 1:14), unlike Jews in Eretz Yisrael, whose holidays were disrupted by searches and tax collection of local Roman officials. Babylonian scholars, he says, dress distinctively because they are foreigners, not because they lack Torah; and Rav Yosef adds that they in fact contribute richly to Torah development (Isaiah 27:6).

Finally, the sugya turns to non-Jews' (spiritual) “pollution”. R' Yoḥanan ties it to historical processes: the primordial contamination from the serpent (in the Book of Genesis) persisted in humanity until the Giving of the Torah at Sinai, where it ceased for Israel. Rav Ashi adds that converts were spiritually present at Sinai. R' Abba bar Kahana, however, argues impurity ended earlier—when Jacob fathered twelve pure sons, unlike Abraham and Isaac, where for each, one of their two sons was wicked.

Outline

Intro

The Passage - Why Are Babylonian Birds Fat? Eretz Yisrael Amoraim Probe the Culture of Babylonia (Shabbat 145b)

1. R' Ḥiyya bar Abba and R' Asi have an exchange about four questions—about Babylonian fowl, festivals, and scholars, and about non-Jews

2. R' Yoḥanan rebukes them for speculating--speak only when knowledge is as certain as incest prohibitions - Proverbs 7:4

3. R' Yoḥanan - Babylonian fowl are fatter because they were not exiled - Jeremiah 48:11

4. R' Yehuda - Judean animals and birds were exiled for 52 years - Jeremiah 9:9

5. R' Yaakov citing R' Yoḥanan - All exiled species returned except mackerel; Rav - Babylonian waters return via Eitam Spring, carrying fish with them

6. R' Yoḥanan - Joyous Babylonian festivals not under Hosea/Isaiah’s curse - Hosea 2:13; Isaiah 1:14

7. R' Elazar - God is burdened by Israel's sins and must decide which punishment to bring - Isaiah 1:14

8. Festivals in Eretz Yisrael are often disrupted by local Roman officials

   1. R' Yitzḥak - Roman troops came to Tzippori on every Festival

   2. R' Ḥanina - Roman officials came to Tiberias on every Festival

9. R' Yoḥanan - Babylonian scholars wear distinctive clothing because they are not natives

10. Rav Yosef - Babylonian scholars cause Torah to “bud and blossom” - Isaiah 27:6

11. R' Yoḥanan - Non-Jews retain spiritual impurity because they did not stand at Sinai - Deuteronomy 29:13–14

12. Rav Ashi - Converts were spiritually present at Sinai via their guardian angels - Deuteronomy 29:13–14

13. R' Abba bar Kahana - Impurity ceased after 3 generations: Jacob fathered 12 unblemished sons

The Passage

Shabbat.145b.10-146a.2

R' Ḥiyya bar Abba and R' Asi have an exchange about four questions—about Babylonian fowl, festivals, and scholars, and about non-Jews

While R' Yoḥanan naps, R' Ḥiyya bar Abba and R' Asi discuss.

יתיב

1. רבי חייא בר אבא

2. ורבי אסי

קמיה דרבי יוחנן,

ויתיב רבי יוחנן

וקא מנמנם.

Apropos relations between the Jews of Eretz Yisrael and Babylonia, the Talmud relates:

1. R' Ḥiyya bar Abba

2. and R' Asi

were sitting before R' Yoḥanan,

and R' Yoḥanan was sitting

and dozing.

In the meantime the two of them conversed.

R' Ḥiyya bar Abba asked R’ Asi four questions, and R’ Asi responded to each one:¹

1. Why Babylonian fowl (עופות) are fat (שמנים): R' Asi pushes back on the implication that Babylonian fowl are superior, asserting Eretz Yisrael fowl are fatter in the “Gaza wilderness” (מדבר עזה).

2. Why Babylonian holidays (מועדים) are joyous: R’ Asi flips it: the Babylonians are poor (and therefore feast only on holidays).

3. Why Babylonian scholars (תלמידי חכמים) wear distinctive (מצויינין) clothing: Because they lack Torah expertise (and therefore rely on clothing to gain respect).

4. Why non-Jews are impure:² Because they eat crawling creatures.³

אמר ליה רבי חייא בר אבא לרבי אסי:

1. מפני מה עופות שבבבל שמנים?

   1. אמר ליה: כלך למדבר עזה, ואראך שמנים מהן.

2. מפני מה מועדים שבבבל שמחים?

   1. מפני שהן עניים.

3. מפני מה תלמידי חכמים שבבבל מצויינין?

   1. לפי שאינן בני תורה.

4. מפני מה גוים מזוהמים?

   1. מפני שאוכלין שקצים ורמשים.

1. R’ Ḥiyya bar Abba said to R’ Asi: For what reason are the fowl in Babylonia fatter than those in Eretz Yisrael?

   1. He said to him: This is not at all the case; go to the desert of Gaza in Eretz Yisrael, and I will show you fowl that are fatter than them.

2. R’ Ḥiyya bar Abba then asked: For what reason are Festivals in Babylonia more joyous than those in Eretz Yisrael?

   1. R' Asi answered him: Because in Babylonia they are poor, and it is only on Festivals that they have a lot to eat, which causes them to rejoice.

3. R' Ḥiyya then asked: For what reason are Torah scholars in Babylonia distinguished by their special rabbinic garb?

   1. R' Asi answered: Because they are not well-versed in Torah. If they would not distinguish themselves by dressing differently, they would not be respected for their Torah knowledge.

4. He then asked: For what reason are non-Jews ethically contaminated?

   1. He answered: Because they eat abominable creatures and crawling things, and that causes bad character traits.

R' Yoḥanan rebukes them for speculating--speak only when knowledge is as certain as incest prohibitions - Proverbs 7:4

He chastises them—addressing them as “children” (דרדקי)—for speaking without clear knowledge, quoting Proverbs 7:4 to emphasize that only things as obvious as incest prohibitions (specifically, that a sister is sexually forbidden) should be asserted.⁴

איתער בהו רבי יוחנן,

אמר להו:

דרדקי!

לא כך אמרתי לכם:

״אמור לחכמה אחותי את״ —

• אם ברור לך הדבר כאחותך שהיא אסורה לך —

  • אומרהו,

• ואם לאו —

  • לא תאמרהו.

R' Yoḥanan woke up due to their discussion

and said to them:

You children!

did I not tell you this,

that the verse “Say to wisdom: You are my sister, and call understanding your kin” (Proverbs 7:4) means that

• if the matter is as clear to you as the fact that your sister is forbidden to you --

  • say it,

• and if not --

  • do not say it;

and these explanations that you offered are unfounded.

R' Yoḥanan - Babylonian fowl are fatter because they were not exiled - Jeremiah 48:11

R' Yoḥanan asserts that Babylonian fowl are fatter because they were not exiled, unlike those of Eretz Yisrael.

He cites Jeremiah's description of Moab, who "has not gone into captivity," as retaining its “taste and scent.”⁵

אמרו ליה: ולימא לן מר איזה מהן?

מפני מה עופות שבבבל שמנים?

מפני שלא גלו,

שנאמר:

״שאנן מואב מנעוריו

ושקט הוא אל שמריו

ובגולה לא הלך״.

They said to him: Then will the Master tell us the answers to some of them?

He said to them: Why are the fowl in Babylonia fatter than those in Eretz Yisrael?

Because they were not exiled,

as it says:

“Moab has been at ease since his youth

and he has settled on his lees, and he was not emptied from vessel to vessel

and did not go into captivity; therefore his taste remained in him and his scent did not change” (Jeremiah 48:11).

Apparently, one who is not exiled retains his strength.

R' Yehuda - Judean animals and birds were exiled for 52 years - Jeremiah 9:9

A baraita adds that even Judean animals were exiled: the word ‘behema’ ( בהמה) is numerical value (גימטריא - ‘gematria’) 52, symbolizing a 52-year desolation when no animals were present (Jeremiah 9:9).

והכא מנלן דגלו?

דתניא,

רבי יהודה אומר:

חמשים ושתים שנה לא עבר איש ביהודה,

שנאמר:

״על ההרים אשא בכי ונהי וגו׳

מעוף השמים ועד בהמה נדדו הלכו״,

״בהמה״ בגימטריא חמשין ותרתין הוו.

And here in Eretz Yisrael, from where do we derive that even the animals and birds were exiled?

As it was taught in a baraita:

R' Yehuda says that

no person passed through the land of Judea for 52 years,

as it is stated:

“I will raise crying and wailing for the mountains and a lamentation for the pastures of the wilderness, for they have been burned, with no person passing through, and they do not hear the voice of the cattle,

from the bird of the heavens to the beast [behema, spelled beit, heh, mem, heh], all have fled and gone” (Jeremiah 9:9).

Behema has a numerical value of 52, alluding to the fact that no one passed through for 52 years.

From the verse cited in this baraita, it is clear that even the animals and birds were exiled, as it states: “All have fled and gone.”

R' Yaakov citing R' Yoḥanan - All exiled species returned except mackerel; Rav - Babylonian waters return via Eitam Spring, carrying fish with them

R' Yaakov says in R' Yoḥanan’s name: all exiled species returned, except the “Spanish colias” (=mackerel),⁶ a weak-spined fish.

A hydrological note is added: Babylonian water returns underground to the Eitam Spring,⁷ carrying fish with it—except for this one, which lacks the strength to swim upstream.

אמר רבי יעקב, אמר רבי יוחנן:

כולן חזרו,

חוץ מקולייס האיספנין,

דאמר רב:

הני מדרי דבבל מהדרי מיא לעין עיטם.

והאי, כיון דלא שריר שדריה לא מצי סליק.

R' Ya’akov said that R' Yoḥanan said:

They all returned

except for the kolyas ha’ispanin,

as Rav said:

Those inclines of Babylonia

return the water through underground watercourses to the spring of Eitam in Eretz Yisrael, and the fish also returned through these watercourses.

And this fish, the kolyas, because its spine is not strong, it could not ascend these watercourses and did not return to Eretz Yisrael.

R' Yoḥanan - Joyous Babylonian festivals not under Hosea/Isaiah’s curse - Hosea 2:13; Isaiah 1:14

R' Yoḥanan rejects the poverty-based answer for joyous Babylonian festivals.

Instead, he claims the cause is a curse found in Hosea and Isaiah, which applies only to Eretz Yisrael.

מפני מה מועדים שבבבל שמחים?

מפני שלא היו באותה קללה,

דכתיב:

״והשבתי כל משושה

חגה חדשה ושבתה וכל מועדה״.

וכתיב:

״חדשיכם ומועדיכם שנאה נפשי

היו עלי לטורח״.

R' Yoḥanan continued to answer the questions of R' Ḥiyya bar Abba and R' Asi:

For what reason are the Festivals in Babylonia more joyous than those in Eretz Yisrael?

Because they were not included in that curse with which Eretz Yisrael was cursed,

as it is written:

“And I will cause all of her happiness to cease,

her Festival, her New Moon, and her Shabbat and all her Festivals” (Hosea 2:13).

And it is also written:

“My soul hates your New Moons and your Festivals;

they are a burden to Me; I am weary to bear them” (Isaiah 1:14).

R' Elazar - God is burdened by Israel's sins and must decide which punishment to bring - Isaiah 1:14

Isaiah's phrase “a burden to Me” is taken literally—God complains that He must determine which “harsh decree (גזירה)“ to inflict on the sinning Jewish community.

מאי ״היו עלי לטורח״?

אמר רבי אלעזר:

אמר הקדוש ברוך הוא:

לא דיין לישראל שחוטאין לפני,

אלא שמטריחין אותי לידע איזו גזירה קשה אביא עליהן!

What is the meaning of the phrase: “They are a burden to me”?

R' Elazar said that

God said:

Is it not enough for the Jewish people that they sin before Me,

that they also burden Me to know which harsh decree I will bring upon them?

Festivals in Eretz Yisrael are often disrupted by local Roman officials

R' Yitzḥak - Roman troops came to Tzippori on every Festival

Festivals in Eretz Yisrael (specifically, in the Galilee) were often disrupted by local Roman troops: searches (בולשת) in Tzippori and tax collection in Tiberias.

(In contrast, Babylonia was spared such decrees.)

אמר רבי יצחק:

אין לך כל רגל ורגל

שלא באתה בולשת לציפורי.

R' Yitzḥak said:

Because of this curse, there is not a single Festival

on which troops did not come to Tzippori to conduct searches or to collect taxes.

R' Ḥanina - Roman officials came to Tiberias on every Festival

ואמר רבי חנינא:

אין לך כל רגל ורגל

שלא בא לטבריה

1. אגמון

2. וקמטון

3. ובעל זמורה.

And R' Ḥanina said:

There is not a single Festival

on which did not come to Tiberias to collect taxes Roman officials,

1. an egmon⁸

2. and a kamton

3. and a branch bearer,

thereby disrupting the festive celebrations.

R' Yoḥanan - Babylonian scholars wear distinctive clothing because they are not natives

R' Yoḥanan says Babylonian scholars wear distinct garments because they are foreigners.

A folk saying affirms this: “In one’s own town, it’s the name;⁹ elsewhere, it’s the clothes (תותבאי)”.

מפני מה תלמידי חכמים שבבבל מצויינין?

לפי שאינן בני מקומן.

דאמרי אינשי:

• במתא --

  • שמאי,

• בלא מתא —

  • תותבאי

For what reason are the Torah scholars in Babylonia distinguished by special garb?

Because they are not native to that place and therefore require special dress to distinguish themselves,

as people say in the folk expression:

• In my own city --

  • I am honored for my name;

• in a place that is not my own city --

  • I am honored for my clothing.

Rav Yosef - Babylonian scholars cause Torah to “bud and blossom” - Isaiah 27:6

״הבאים ישרש יעקב

יציץ ופרח ישראל״.

תני רב יוסף:

אלו תלמידי חכמים שבבבל,

שעושין ציצין ופרחים לתורה.

The Talmud then praised the rabbis of Babylonia by interpreting the verse:

“In days to come Jacob will take root,

Israel will bud (יציץ) and blossom (פרח)” (Isaiah 27:6).

Rav Yosef taught:

These are the Torah scholars in Babylonia,

who add “buds (ציצין) and blossoms (פרחים)” to the Torah.

R' Yoḥanan - Non-Jews retain spiritual impurity because they did not stand at Sinai - Deuteronomy 29:13–14

R' Yoḥanan offers a historical rationale for why non-Jews have “pollution”:¹⁰ the snake’s contact with Eve¹¹ introduced it.

Israel was purified of it at the historic event of the Giving of the Torah at Sinai; non-Jews were not.

מפני מה גוים מזוהמין?

שלא עמדו על הר סיני.

שבשעה שבא נחש על חוה

הטיל בה זוהמא,

• ישראל שעמדו על הר סיני —

  • פסקה זוהמתן,

• גוים שלא עמדו על הר סיני —

  • לא פסקה זוהמתן.

R' Yoḥanan then explained to them:

Why are non-Jews ethically contaminated?

It is because they did not stand on Mount Sinai.

As when the snake came upon Eve, i.e., when it seduced her to eat from the Tree of Knowledge,

it infected her with moral contamination, and this contamination remained in all human beings.

• When the Jewish people stood at Mount Sinai --

  • their contamination ceased,

• whereas non-Jews did not stand at Mount Sinai --

  • and their contamination never ceased.

Rav Ashi - Converts were spiritually present at Sinai via their guardian angels - Deuteronomy 29:13–14

Rav Aḥa bar Rava asks: what about converts?

Rav Ashi replies: their guardian angels¹² were present at Sinai, as implied by Deuteronomy 29:13–14, where Moses says that the covenant was made both with “those here with us today”, as well as with “those not here with us today” (i.e. future generations).

אמר ליה רב אחא בריה דרבא לרב אשי: גרים מאי?

אמר ליה:

אף על גב דאינהו לא הוו,

מזלייהו הוו.

דכתיב:

״את אשר ישנו פה עמנו עומד היום לפני ה׳ אלהינו

ואת אשר איננו פה וגו׳״

Rav Aḥa, the son of Rava, said to Rav Ashi: What about converts? How do you explain the cessation of their moral contamination?

Rav Ashi said to him:

Even though they themselves were not at Mount Sinai,

their guardian angels were present,

as it is written:

“It is not with you alone that I make this covenant and this oath, but with he that stands here with us today before YHWH our God,

and with he that is not here with us today” (Deuteronomy 29:13–14), and this includes converts.

R' Abba bar Kahana - Impurity ceased after 3 generations of biblical Patriarchs: Jacob fathered 12 unblemished sons

This final view, attributed to R' Abba bar Kahana, posits a three-generation process of biblical Patriarchs: Abraham’s line was still affected (due to Ishmael), Isaac likewise (due to Esau), but Jacob’s 12 sons were “flawless”.¹³

ופליגא דרבי אבא בר כהנא.

דאמר רבי אבא בר כהנא:

עד שלשה דורות לא פסקה זוהמא מאבותינו:

1. אברהם

   1. הוליד את ישמעאל,

2. יצחק

   1. הוליד את עשו,

3. יעקב

   1. הוליד שנים עשר שבטים

   2. שלא היה בהן שום דופי.

The Talmud points out that this opinion disagrees with R' Abba bar Kahana,

as R' Abba bar Kahana said:

Until 3 generations passed, the moral contamination did not cease from our forefathers:

1. Abraham

   1. fathered Ishmael, who was of lowly moral stature;

2. Isaac

   1. fathered Esau;

3. finally, Jacob

   1. fathered 12 tribes

   2. in whom there was no flaw.

R' Abba bar Kahana holds that the moral contamination ceased in the Patriarchs long before the Revelation at Sinai.

1. In 3 of the first 4 exchanges, the same pattern plays out: R' Ḥiyya bar Abba asks why some Babylonian [X] is so good. R’ Asi responds by minimizing its value — either by claiming that Eretz Yisrael has something even better (as in the first case), or by explaining that Babylonian [X] is merely a side effect of something generally negative.

Regarding the fourth and final question—'why are non-Jews (spiritually) polluted'—the connection isn't obvious. See my later note: a related discussion occurs specifically in reference to Babylonian non-Jews, so this exchange here may also be regarding Babylonian non-Jews in particular.

2. מזוהמים - literally: “polluted”.

3. שקצים ורמשים.

Compare the related Talmudic argument made in my “Pt3 Uncovered Liquids and Ritual Boundaries: Gentile Wine and the Risk of Snake Venom (Avodah Zarah 30a-31b)“, section “Explanation for why non-Jews don't die after drinking uncovered water: non-kosher diet“, where I summarize:

Shmuel then tells Ḥiyya bar Rav something “excellent” that his father, Rav, once said:

The local non-Jews, who are swollen, who drink exposed liquids, don’t die from the venom in the liquids because they consume “repugnant creatures and creeping animals”, which warm (חביל) their bodies.

And see my notes there.

4. He then offers in the following sections alternative explanations, each supported with biblical verses.

5. It’s worth noting that the Talmud elsewhere cites the same verse in a somewhat similar context: Ahasuerus’ Jewish advisers explaining why their advice can’t be expected to be as good as that of other ethnicities’; see my “Talmudic Interpretations of the Book of Esther: Esther 1:10-14 (Megillah 12b)“, section “The Jewish Sages Avoid Judging Vashti’s Fate (Esther 1:13-14, Jeremiah 48:11)“, where I summarize:

The Talmud identifies the "wise men who knew the times" (Esther 1:13) as the Jewish Sages, renowned for their knowledge of intercalating (לעבר) years and setting the calendar.

Ahasuerus commands the Sages to judge Queen Vashti’s fate. However, they hesitate, fearing the consequences of either decision: if they order her execution, the king may regret it when sober; if they spare her, they would be seen as tolerating royal disrespect.

To avoid ruling, they claim that, since the destruction of the (First) Temple and their exile, they lack the wisdom to judge capital cases (דיני נפשות). Instead, they suggest consulting the Ammonites and Moabites, who, unlike the Jews, have remained settled in their land.

They support their reasoning with Jeremiah 48:11, which describes Moab as retaining its judgment and character due to its stability.

Ahasuerus accepts their advice and turns to his non-Jewish advisors for counsel (Esther 1:14 - as stated in the next section).

6. קולייס האיספנין - “Spanish colias”, second word is Greek.

See Jastrow:

קולייס, קוליאס, קוליס m[asculine]

(κολίας - kolĭ́ās) colias, a kind of tunny fish.

See Wiktionary on this latter fish:

Atlantic chub mackerel (Scomber colias)

And see Hebrew Wikipedia, “קלי הבישול“, section “זיהויו של קולייס האספנין“, my translation:

Rabbi Menachem di Lonzano identifies the kulyas ha-ispanin as a fish called colias that comes from Spain (Hispania).

7. עין עיטם.

On this spring, see Hebrew Wikipedia, my translation:

Ein Eitam is a spring in the Jerusalem area mentioned in Talmudic literature.

Water from it was brought to the Temple for filling the mikva'ot and other purposes.

It is also mentioned as one of the proposed sites for building the First Temple.

The identification of the spring referred to by this name is disputed, but the most widely accepted theory identifies it with a spring located south of Jerusalem, near Artas and Solomon's Pools.

See also Wikipedia, “Solomon's Pools“, section “Name“:

The pools are named and traditionally associated with King Solomon and linked to the passage in the Book of Ecclesiastes 2.6: "I made myself pools from which to water the forest of growing trees."

Josephus wrote that Solomon enjoyed the beauty of the water-rich "Etham" (one of the main springs is called Ein Eitam = Hebrew: עין עיטם).

The pools are in close proximity to the ancient town of ʻEiṭam (now Khirbet al-Khuaḥ) and the spring known as ʻAin ʻEiṭam.

Legend has it that the king built the pools for his many wives, so that they could bathe in their waters.

8. אגמון - hegemon.

The Talmud often mentions this title for local Roman officials: hegemon; see my previous note on this.

9. I.e., “name” (=reputation) is enough; one doesn’t need to wear special clothing to impress.

10. ‘zuhama’ - spiritual contamination/pollution.

11. In the Garden of Eden, as described in the beginning of the Book of Genesis.

There’s likely a sexual connotation here, see my extended note on this, where I cite this sugya here, in my “Pt2 Dealing with Dangerous Snakes: Swallowing, Bites, Pursuits, and Attacks (Shabbat 109b-110a)“, on section “A Woman Being Sexually Pursued by a Snake“.

12. מזלייהו - literally: “their luck, fortune”.

Compare the Roman concept of genius, see Wikipedia, “Genius (mythology)“:

In Roman religion, the genius […] is the individual instance of a general divine nature that is present in every individual person, place, or thing.

Much like a guardian angel, the genius would follow each man from the hour of his birth until the day he died.

13. לא היה בהן שום דופי - “in whom there was no flaw (דופי)“.

Thus, for R' Abba, purity was achieved at the time of Jacob, not via the Giving of the Torah at Sinai.

For another example of this idiom for “flawless”, see Sanhedrin.102a.8:

״וימצא אתו אחיה השילוני הנביא בדרך

והוא מתכסה בשלמה חדשה

ושניהם לבדם בשדה״

מאי ״בשלמה חדשה״?

אמר רב נחמן:

כשלמה חדשה

• מה שלמה חדשה —

  • אין בה שום דופי

• אף תורתו של ירבעם —

  • לא היה בה שום דופי

The verse states:

“And the prophet Ahijah the Shilonite found him [=Jeroboam] on the way,

and he [=Jeroboam] was clad in a new [ḥadasha] garment,

and the two were alone in the field.”

What is taught by the phrase “in a new garment”?

Rav Naḥman says:

It was like a new garment;

• just as a new garment —

  • has no imperfection (אין בה שום דופי)

• so too, the Torah studies of Jeroboam at that time —

  • had no imperfection.