The Previous Lubavitcher Rebbe displayed two contrasting modes of behavior with respect to dwelling in the Sukkah were observed: He was scrupulous with regard to eating and drinking exclusively in the Sukkah, so much so that he would not even drink water outside it.1 But he slept in his house.2

It would seem that the opposite should have been the case: The obligation to sleep in a Sukkah carries a greater stringency than that of eating and drinking there. For one may eat a light repast (and surely drink water) outside the Sukkah, while even a short nap is prohibited.3

Now, it is true that difficulties resulting from time and place free a person from the obligation to sleep in the Sukkah, as we find the law4 that “where it is painful to sleep in the Sukkah because of the cold … it is not necessary to sleep in the Sukkah … for whoever is distressed by dwelling in the Sukkah is free from the obligation to dwell there.”

Nevertheless, this does not resolve the question concerning the Previous Rebbe’s conduct, inasmuch as difficulties such as these had absolutely no bearing on his eating and drinking. Even when it was raining — during which time one may surely eat in the house5 — he would not eat outside the Sukkah.

The Mitteler Rebbe once asked his chassidim:6 “How is it possible to sleep in Makkifim d’Binah?” This means that the Sukkah is illuminated by an extremely lofty level of holiness. As such, the Mitteler Rebbe expressed astonishment that his chassidim could sleep there, in keeping with the verse:7 “Behold, G‑d is to be found in this place, and I knew it not,” upon which Rashi comments: “Had I known, I would not have slept in so sacred a place.”

So when one is clearly aware of the holiness of the Sukkah, the law allows one to sleep in his home. For when a person knows he will be unable to fall asleep in the Sukkah, he is permitted to sleep in his house.

This is why the Previous Rebbe did not sleep in the Sukkah: While in the Sukkah he felt the tremendous revelation of the holiness. This kept him from being able to sleep there.

However, this only explains the conduct of the Previous Rebbe and other select individuals who were able to actually feel the holiness that manifests itself in the Sukkah. We observe, however, that even chassidim who were unable to feel this tremendous sanctity failed to sleep in the Sukkah.

The explanation is as follows: As loyal and dedicated followers of the Rebbeim, chassidim imitate their behavior.8 Especially so, since their inability to conduct themselves in a manner similar to their Rebbeim would cause them pain — in turn freeing them from the obligation to sleep in the Sukkah.

Particularly so, as the Mitteler Rebbe demanded to know of his chassidim how it was possible for them to sleep in the Sukkah. Therefore a chassid who is close to his Rebbe finds it impossible to sleep in the Sukkah. For although the sacred illumination of the Sukkah does not disturb his sleep, he is pained by this very fact.

And even an individual who is untroubled by his inability to feel the holiness of the Sukkah is pained if the saying of the Mitteler Rebbe does not penetrate him.

Accordingly, the very fact that he is able to sleep without pain in the Sukkah causes him pain. And one who is pained is free from sleeping in the Sukkah.

Based on Likkutei Sichos, Vol. XXIX, pp. 211-219.