פירוש על סוכה 2:3

בראש העגלה – even though it is unsteady and not fixed.

Introduction There are two interrelated subjects in this mishnah: 1) building a sukkah in a strange place; 2) entering the sukkah on the festival. As background we should note that on a festival or Shabbat it is forbidden to climb a tree, lest one break off a branch, which is prohibited on Shabbat and a festival. It is also forbidden to ride on an animal on a festival or Shabbat. The mishnah uses the language “go up into” the sukkah because sukkot were often built on the flat roofs of their homes. Nevertheless, not all of these mishnayot describe actually going up into a sukkah.

בראש הספינה – on the sea, and the wind controls there and uproots it.

One who makes his sukkah on the top of a wagon, or on the deck of a ship, it is valid and one may go up into it on the festival. One can build a sukkah on a wagon or on a ship and one can enter into it on Shabbat. The Talmud explains that the sukkah has to be strong enough to stand up to a wind of common strength. One who builds such a sukkah can enter into on the festival because there is no prohibition of getting onto a ship or a wagon on the festival. Indeed, there is a well-known story in the Talmud of rabbis traveling on Sukkot and making a sukkah on the ship. Assumedly, Rabbi Judah who in yesterday’s mishnah stated that a sukkah made using a bed’s bedposts is invalid, would also invalidate a sukkah made on a wagon or ship.

כשרה – for it is a called a dwelling/residence. And this can withstand the winds found on dry land.

If he made it on the top of a tree, or on the back of a camel, it is valid, but one may not go up into it on the festival. A sukkah made on top of a tree or on the back of a camel is also a valid sukkah (I have actually seen such a thing in Neot Kedumim, near where we live in Israel). However, since it is forbidden to climb a tree or ride on an animal on Shabbat or a festival, these sukkot could only be used during Hol Hamoed, the non-festival days of Sukkot.

ועולין לה ביום טוב – since our Mishnah needs to teach the conclusion that they don’t ascend [to the Sukkah], the beginning of the Mishnah teaches, we ascend/go up.

If the tree [formed] two [walls] and one was made by the hands of man, or if two were made by the hands of man and one was formed by the tree, it is valid, but one may not go up into it on the festival. In this and the next section the person doesn’t make his sukkah in a tree but rather he uses a tree to support the roof of his sukkah. A tree can be used to support the sukkah’s wall even though the leaves may not count as skhakh when they are attached to the tree. A sukkah must have at least three walls, so if he uses a tree to support even one these three walls he cannot enter the sukkah on the festival because that would be considered using the tree.

בראש האילן – he established his seat at the top and he made there partitions/walls and the cover of the festive booth (i.e., a ceiling of twigs or matting).

If three walls were made by the hands of man and one was formed by the tree, it is valid and one may go up into it on the festival. This is the general rule: in any case in which if the tree was removed the [sukkah] could stand on its own, it is valid and one may go up into it on the festival. If, however, he has four walls and only one supported by the tree then the sukkah would be valid and would be able to stand even without the tree. Hence, he may enter this sukkah on the festival because by doing so he is not actually using the tree. The tree-wall is superfluous. The mishnah now summarizes this rule citing a general principle.

כשרה – on the Intermediate Days of the Festival.

ואין עולין לה ביו"ט – for it was decreed by the Rabbis that we don’t ascend upon a tree and we don’t use it lest he detach [a branch].

שתים באילן – he supported most of the floor of the Sukkah on the tree, and he made around it at the top of the tree two walls and one was man-made on the ground and it supported the bottom of the Sukkah in the middle of the wall that he made on the ground and raised the wall from it and raised it ten [handbreadths].

או שתים בידי אדם ואחת באילן – since for if he would take it, the bottom of the Sukkah would fall, and could not stand with the support of two [sides of the Sukkah] that are in the ground, and we don’t ascend it on Yom Tov/Holy Days of the Festival, for one is using the tree.