Siman 634

Even though any house that does not have four amot by four amot is not considered a house at all for any matter: for mezuzah, for a parapet, for plagues, for houses in walled cities, for returning from the battle lines, and one does not place an eruv in it, and it does not have enough for division (Sukkah 3a), and it does not establish an obligation for ma'aser or for vows (Tosafot ibid. in the name of the Yerushalmi), and it is not considered the entrance of her father's house regarding a betrothed maiden (ibid.), because people do not dwell in it (Gemara ibid.); nevertheless, regarding sukkah, which is a temporary dwelling, the tradition has come that seven tefachim by seven tefachim is sufficient, so that a person's head and the majority of his body may enter it, along with a small table of a tefach by a tefach, and he fulfills his obligation with it.

And even though it is not fit to sleep in the manner of a person lying down, nevertheless, he can sleep sitting, leaning against the wall. And specifically seven by seven. But if the length is less than seven and the width is much more than seven, or vice versa, even though in the total there would be more than this measure—nevertheless it is not effective; for whenever the length or the width is less than this measure, it is impossible for a person to sit in it properly (Taz and Magen Avraham). This is not like the one who wants to validate it in a long and narrow case. And even though regarding the matter of mezuzah and other things—this manner is effective, that is regarding four amot by four amot, where there is a spacious area, and not regarding seven by seven. And for the size of the sukkah—it has no measure. And even though regarding height there is a measure of twenty amot—nevertheless in length and width the sukkah has no upper measure.

And if it is circular – it must be surrounded by a cord of twenty-nine tefachim and two-fifths, for in this there is, according to the calculation of measurement, a square of seven by seven. And even in a very large sukkah, if in one place there is a projecting corner that does not contain seven by seven – it is forbidden to sit there; since the place is narrow and is not fit for sitting – it is not included in the sukkah (Magen Avraham). And there is a proof for this from the Gemara regarding the small rooms of Queen Helene at the beginning of Sukkah, see there. And these seven tefachim by seven tefachim – must be completely vacant, aside from the small table upon which one eats. And even if one placed garments to beautify it, and they diminish it from seven by seven – it is invalid, because there will not remain a place to sit. And it is not similar to the height of ten in the previous siman, for there, there is width and length as is proper.

Our teacher, the Beit Yosef, wrote: One whose head and most of his body were in the sukka, but his table was outside the sukka, and he ate—it is as if he did not eat in the sukka, even if it is a large sukka, as a decree lest he be drawn after his table. Thus far his words. And he ruled like the Rif and the Rambam in chapter six, law 8, that just as the minimum size of a sukka must be enough for his head, most of his body, and his table, likewise in a large sukka one may not sit at the entrance and eat from his table that is outside the sukka. However, the Rosh, and the Tur, and several of the Geonim ruled that in this there is no prohibition, as the Tur wrote.

One should be precise regarding the wording of our teacher, the Beit Yosef, who wrote: "it is as if he did not eat in the sukkah." But according to Torah law, he certainly fulfilled his obligation, since it is only due to a decree lest he be drawn after his table! And indeed, the wording of the Rambam who wrote: "One whose head and most of his body were in the sukkah, and his table was outside the sukkah, and he eats – behold, this is forbidden, and it is as if he did not eat in the sukkah... a decree etc." Thus far his words. And he elaborated intentionally, and this is the explanation: Behold, this is forbidden by rabbinic law, and they were stringent upon him as if he did not eat in the sukkah. But according to Torah law – he certainly fulfilled his obligation. However, our teacher, the Beit Yosef, who wrote explicitly "it is as if he did not eat in the sukkah" – it implies that even according to the Torah it is so, and this is impossible. And it appears that the matter is as follows: That certainly it is only rabbinic, but the sages established it such that even according to the Torah he does not fulfill his obligation, because the ruin is near. And they were compelled to this from the wording of the Mishnah (28a), as they said regarding this that one who does so – has never fulfilled the mitzvah of sukkah in his days. And this is what the Rambam says: "Behold, this is forbidden." Meaning: by rabbinic law, and they made it as if he did not eat according to the Torah. And our teacher, the Beit Yosef, also intended this, but he was brief in his words (and so wrote the Tosafot in Berakhot 11a and at the beginning of Sukkah). And if part of the table stands in the sukkah, and part of it is outside the sukkah – it is permitted (Magen Avraham).