Mishnayos Sukkah Perek 2 Mishnah 4

והאילנות דפנות לה כשירה – and this is the case where the trees are thick and strong and don’t move when a frequent wind comes. And it is also necessary to fill between the branches with straw and stubble so that wind will not move them, and all partitions that cannot stand with frequent wind is not a partition.

שלוחי מצוה פטורים – for someone who engages with [the performance of] a commandment/Mitzvah is exempt from the Commandment, and not only are they exempt at the time that they are engaged with [another] Mitzvah, but even at a time when they are not engaged in it, for example, a person who goes to receive and welcome his teacher or to redeem captives is exempt, even at the time of his resting.

חולין ומשמשיהן פטורים – and even those who are simply sick, and he who permits to annual a positive commandment of the Torah because of a mere illness, and is pained because of bad smell or because of bed-bugs and fleas where he is exempt, and similarly, those who walk on the path and those who guard the gardens and orchards, the Rabbis exempted them from the Sukkah, the reason is because it is written (Leviticus 23:42): “You shall live/dwell in booths [seven days; all the citizens of Israel shall live in booths],” like the way you live, and wherever there is a thing that because of that, he would leave from his dwelling, he can also leave from his Sukkah. But one who makes his Sukkah from the outset in a place that is appropriate to be in pain while eating or sleeping, such as in a place where he is afraid of robbers while sleeping, but he is not afraid of thieves or robbers while eating, even regarding eating, he does not fulfill his obligation in that Sukkah, for since it is not appropriate to do within it all of his needs of eating and drinking and sleeping, for we require where he can reside, and this is a case where it is not like “living/residing.”

אוכלים ושותים עראי – a small amount to remove his hunger, and his intention is to eat a meal afterwards.