Rav Shimon Szimonowitz, Machon Aleh Zayis
Rav Huna was on the road and grew thirsty. He would not drink until he reached a sukkah. (Yerushalmi, cited in Magen Avraham 640:16)
No Comparison
This episode illustrates one of three curious chumros in hilchos sukkah that the Magen Avraham records in the name of the Yerushalmi. The second chumrah: a watchman may sleep outside the sukkah only when he stands guard protecting lives; one who merely guards property may not. The third: the Amora Avduma slept outside his store, and Rabi Chanina instructed him to sleep in a sukkah. Accordingly, rules the Magen Avraham, even one who usually eats in his store, away from home, must eat in the sukkah on Sukkos.
These rulings run counter to a principle found repeatedly in the Bavli: "Teishvu k'ein taduru — Dwell in the sukkah as you dwell at home." The obligation of sukkah applies only to what a person would otherwise do in his house. As such, the Bavli (Sukkah 26a) permits watchmen protecting property to sleep outside the sukkah, since they would normally sleep outside their houses in this situation (see Tosafos s.v. pirtzah). By the same token, one who eats at his workplace the entire year ought to be permitted to eat there on Sukkos. Travelers, too, are exempt from eating and drinking in the sukkah, because they eat away from home all year round (Tosafos s.v. holchei).
However, for all its ubiquity in Talmud Bavli and in the Rishonim, the expression "Teishvu kein taduru" appears nowhere in Talmud Yerushalmi. This would explain all these chumros, but it would require examining the Yerushalmi's approach to many halachos of sukkah known from the Bavli.
Money or Life
The Bavli (Sukkah 26a) teaches that watchmen of gardens and orchards are exempt from the mitzvah of sukkah. According to Abaye, the exemption rests on teishvu kein taduru: The Torah bids a man leave the house he inhabits all year and dwell in the sukkah together with his beds, utensils, and bedding (Rashi) — and a watchman cannot haul all these out to his post, on Sukkos or during the rest of the year. According to Rava, the exemption is based on the adage "Pirtzah koraʼah laganav — A breach beckons the thief," the danger that a thief, seeing the watchman settled in his sukkah, might sneak in and steal the produce.
In Alim (Haazinu-Sukkos 5783), I pointed out that according to the Rambam, Rava does not merely offer a second reason; he rejects Abaye's derashah (and the Rambam rules accordingly — Hilchos Sukkah 6:4). Tosafos (s.v. pirtzah), on the other hand, argue that Rava does acknowledge the derashah of teishvu k'ein taduru.
The Yerushalmi evidently subscribes neither to teishvu kein taduru nor to pirtzah koraʼah laganav; it grants the watchman no exemption unless lives are at stake. This would explain why the Yerushalmi nowhere mentions that a mitzta’er is exempt from the sukkah.
The Yerushalmi's rejection of teishvu kein taduru is the key to many sugyos in which the Yerushalmi diverges from the Bavli.
Kohanim and Women
The Torah exempts women from the mitzvah of sukkah. The Gemara (Sukkah 28b; Kiddushin 34a-b) wonders why a special exemption is necessary, as women are in any event exempt from all time-bound mitzvos. The Gemara answers that the exemption is not self-understood: without it, one would assume women are obligated. The Amoraim disagree as to the reason for that assumption.
Abaye cites the principle of teishvu kein taduru: it is reasonable to think that just as a dwelling houses a man together with his wife, so must the sukkah. Rava points instead to the gezeirah shavah between "the fifteenth day" of Tishrei (the first night of Sukkos) and "the fifteenth day" of Nissan (the first night of Pesach), which would suggest that women are obligated in sukkah just as they are obligated in the mitzvos of Pesach. In the Yerushalmi, this entire discussion is absent.
The Gemara in Arachin (3b) references this principle as well. The beraisa there states that kohanim are obligated in the mitzvah of sukkah. Why is this statement necessary? "Dwelling" means a man living together with his wife; since kohanim are often occupied with the avodah away from home, perhaps they should be exempt. Rashi concludes that as per teishvu kein taduru, a kohen is indeed exempt from sukkah while performing the avodah. The Yerushalmi makes no mention of this discussion either.
Divergent Sources
Rabi Eliezer requires fourteen meals to be eaten in the sukkah, one by day and one at night for seven days, while the Chachamim set no fixed quota (Mishnah Sukkah 27a). According to the Bavli, both opinions are based on teishvu kein taduru. Rabi Eliezer holds that just as one eats one meal by day and one at night in his regular dwelling, so must he do in the sukkah. The Chachamim, in contrast, maintain that just as a man eats when he wishes and refrains when he wishes in his dwelling, the same applies in the sukkah.
In the Yerushalmi, even Rabi Eliezer's requirement of fourteen meals is derived not from k'ein taduru but through a gezeirah shavah from the milu'im (during which the kohanim were commanded to remain at the entrance of the Ohel Moed day and night for seven days).
Dwelling on the Difference
There remains, of course, the beraisa (Sukkah 28b): "Teishvu kein taduru — they said: all seven days a man makes his sukkah his permanent residence and his house his temporary one. How so? If he has fine utensils, he brings them to the sukkah; he brings his fine bedding to the sukkah; and he eats, drinks, strolls, and reviews his learning in the sukkah." This derashah is beyond dispute.
Here, the Yerushalmi comes closest to a derashah of teishvu kein taduru, but the difference in language is significant. The Yerushalmi (Sukkah 2:10) mandates the same conduct — that a man eat and stroll in the sukkah and bring his utensils into it — but the words kein taduru are not used. Instead, the Yerushalmi reads: "Ein teishvu ela dirah 'Teishvu' denotes dwelling as in the pasuk 'virishtem osah vishavtem bah — You shall take possession of it and dwell in it'."
While the Bavli establishes that what a man does at home is the litmus test for the sukkah, the Yerushalmi holds that any act of dwelling must be performed in the sukkah, regardless of whether one would perform it at home.
Sick Leave
The ruling of the Mishnah (Sukkah 2:4) exempting the sick from the sukkah now requires explanation. Both the Bavli (26a) and the Yerushalmi (ibid) clarify that this includes even a choleh she'ein bo sakanah. For the Bavli, the exemption rests on k'ein taduru; but how does the Yerushalmi explain it? Perhaps a choleh is exempt because he is preoccupied with another mitzvah — tending to his health. Alternatively, he is exempt because he is not expected to extend himself while ill to perform a mitzvah.
Either way, the exemption of a choleh would not be unique to hilchos sukkah. Indeed, Rav Elchanan Wasserman (Kovetz Shiurim, 2:46) cites a teshuvah of the Geonim (Teshuvos Hageonim, Lyck 5624, siman 51) that exempts one who is seriously ill from davening. [It is worth noting that Rav Elchanan was agreeable to drawing halachic conclusions from these teshuvos of the Geonim, first published in the nineteenth century. In the same piece he brings proof from the Geonim against the view of the Acharonim that the size of eggs has changed since the time of the Gemara.] The concept of extending the exemption of a choleh to other mitzvos was already published in the eighteenth century in the name of the Rosh, in the collection Besamim Rosh. But the Chasam Sofer dismissed that work as "Kizvei haRosh — fabrications in the name of the Rosh" (Teshuvos Chasam Sofer, Orach Chaim 154, p. 187 Aleh Zayis edition), a suspicion that has long since been substantiated. Therefore, no evidence can be taken from the Besamim Rosh. Rav Dov Ber Trebitsch, a contemporary of the Gra, also extended the exemption of a choleh. In his Revid Hazahav (Achrei Mos, on the pasuk "Vachai bahem" [Vayikra 18:5]), he declares it obvious that a mitzvas aseh is overridden for the sake of a choleh even when his life is not in danger. He proves this from the halachah that a choleh is exempt from sukkah. This source is cited by Rav Zelig Reuven Bengis (Chiddushei Hagrazar, siman 20).
Rained Out
If the Yerushalmi makes no exemption for a person who is uncomfortable in the sukkah (mitzta'er), why does one leave the sukkah when it rains? This halachah cannot be a matter of dispute between the Talmudim, since it is brought in the Mishnah (Sukkah, end of perek 2). Evidently, the Yerushalmi distinguishes between a mitzta'er and a sukkah that has become uninhabitable. The Yerushalmi rules that an uninhabitable sukkah is not a sukkah. When it rains, one is not exempt from the mitzvah; he simply has no sukkah.
The Mishnah permits one to leave the sukkah when the rain could ruin his porridge (mishe'tisrach hamikpah). In the Bavli (29a), this is measured by personal discomfort. Rav Yosef, who was particularly finicky, was in fact permitted to leave the sukkah even when the disturbance was not severe enough to ruin the porridge. Accordingly, the Rema rules that regarding sleep the bar is lowered, and even a drop of rain exempts one from the sukkah (639:7).
By contrast, the Yerushalmi (2:10) points out that the Mishnah does not specify that to leave the sukkah, one's own porridge must be ruined; the exemption depends on whether the rain is strong enough to [theoretically] ruin a porridge (see Tur ibid). This is consistent with its approach that when it rains, the defect lies not in the person's comfort but in the sukkah itself.
Similarly, the Yerushalmi cites the opinion that one who left the sukkah because of the rain must return when the rain stops, even in the middle of the night. It relates that Rabban Gamliel and Rabi Eliezer went in and out of the sukkah all night because it was raining on and off. This is the ultimate proof that the Yerushalmi rejects the exemption of mitzta'er. According to the Bavli (29a), based on the din of mitzta'er, one who was forced out of the sukkah by the rain is permitted to remain inside his house for the rest of the night.
Contextualizing Fleas
These divergent approaches of the Bavli and the Yerushalmi can explain why the Bavli mentions that being inundated with fleas exempts one from sukkah in connection with mitzta'er and choleh, whereas the Yerushalmi mentions a flea-infested sukkah together with a rained-upon sukkah. For the Bavli, the heter is based on teishvu kein taduru; for the Yerushalmi, it is based on the sukkah being rendered uninhabitable.