Of the many mitzvot connected to the holiday of Sukkot, perhaps the most conspicuous is the actual structure of the sukkah (booth) in which we dwell for the entire holiday - and for which the festival itself is named. While the explicit reason for constructing the sukkah is to recall the miraculous exodus from Egypt and G‑d's shelter as we traveled through the Sinai Desert, the Ari explains that, when properly constructed, the sukkah serves as a model of the spiritual worlds and conduit for expanded consciousness, channeling divine benevolence into the Lower Realms.

One of the elements necessary for a valid sukkah is the "schach", the roof of the sukkah, made of organic natural materials resting upon the walls. Chassidic literature teaches that the words "sukkah", as well as "schach", hint at the phrase "perceiving [in Hebrew, 'sochei'] with divine inspiration", used to describe our matriarch Sarah, also known as "Isca" (from the same root letters).

The schach of a kosher sukkah serves as the medium through which we absorb supernal wisdom and understanding….

The Ari teaches that this connection between the schach and divine inspiration, prophecy, or any level of expanded consciousness, is anything but marginal. In fact, the schach of a kosher sukkah in particular serves as the medium through which we absorb supernal wisdom and understanding. Kabbalah presents not only models of spiritual realities in the supernal worlds, but also how we play an active role in their manifestation in This World. In the sukkah, we function in the role of the partzufim of Zeir Anpin and Nukva, resembling immature son and daughter (or chicks in a nest), and the schach functions as an interface with the partzuf of Imma, the nurturing "mother" - not unlike "our mother" Sarah - hovering over her young in her nest, bestowing wisdom and understanding, allowing them to mature, and even giving them a glimpse of the universe from her exalted perspective.

Let us expound upon the matter of the schach of the sukkah. The partitions [of the sukkah] are the netzach, hod, yesod of Imma, in the aspect of Surrounding Light. But the schach is the lower half of tiferet of Imma, from her chest level and below, which resembles schach upon the three partitions within it. And it is known that this part of tiferet is actually the keter of Zeir Anpin - and this is the schach of the sukkah, which "hovers" [in Hebrew "socheach", from the root word for "schach"] over Zeir Anpin and Nukva, which dwell beneath it. This is because each keter [literally "crown"] is in the aspect of Surrounding Light, from the word "koteret" [meaning "crowned", implying "encircled"].

Now, the height of the schach should be no higher than twenty cubits, for a sukkah which is higher than twenty cubits is invalid. The reason for this is that Zeir Anpin and Nukva, which each stand beneath, each have ten sefirot - therefore together they total twenty cubits. And the schach is the keter upon both of them, whose height is particularly constricted to twenty cubits above them. But if it is above twenty cubits, it is invalid.

And even though there is schach over him, if it is above twenty cubits, he is unable to perceive its light….

The reason for this is, as the Sages have written in the Talmud, that when [the height of the sukkah] is up to twenty cubit [or less], a person acknowledges that he is sitting in the shade of the sukkah, etc. [The deeper] meaning of this is that it is known that, regarding all the supernal lights, each person, each one beneath the level of his companion, is unable to reach or perceive beyond his particular level. This is like they say about the souls of the tzaddikim, that each is burned [i.e. damaged] by the canopy of his companion [i.e. by the close proximity to another's domain]

The reason for this is, as the Sages have written in the Talmud, that when [the height of the sukkah] is up to twenty cubit [or less], a person acknowledges that he is sitting in the shade of the sukkah, etc. [The deeper]. And here we see that this "person" which sits beneath this [metaphoric] sukkah is Zeir Anpin and Nukva, Adam and Eve, upon whom it is said, "masculine and feminine He created them, and He called them 'Adam'" (Gen. 5:2). And in particular Zeir Anpin, referred to by the name "Mah" (Havayah spelled out with alefs, whose numerical value equals 45), which has the same numerical value as the word "Adam" [Hebrew for 'person'], as is known.

And this "person" is completely unable to perceive beyond the lower half of the tiferet of Imma. And even though there is schach over him, if it is above twenty cubits, he is unable to perceive its light, and doesn't know that he is sitting in its shelter, and that it [the schach] is hovering over and shining upon him.

And all 100 of these lights pass through this schach….

Now, to clarify the meaning of the word "schach". It is known that the sefira of keter includes all nine sefirot beneath it…. Also [regarding] tiferet of Imma itself, certainly all the lights within her and beneath descend and are transmitted through it [tiferet of Imma]. And so we find two reasons that this is the case, that in this keter all that is below it is included within it: For we know that the lights of Imma, which are drawn into Zeir Anpin are one-hundred lights, which is the secret of the "100 Blessings" that a person should say each day; these are the name Sag [the name Havayah spelled out to equal 63, which is associated with the partzuf of Imma] plus 37, just the spelling-out alone of Sag, which together equal 100; these [numbers] represent the place of both the hidden and the revealed lights of Zeir Anpin (see Shaar Hapasukim, parashat Vayetzei)…. And all 100 of these lights pass through this schach, which is the keter of Zeir Anpin, and are integrated within it, and place their impression [i.e. influence] within it - just that the light of the schach is in the aspect of Surrounding Light, as mentioned above.

And via these perforations of the schach…these lights descend … resembling the stars of the heavens….

It is for this reason that it is called "schach", for the meaning of the term is that it "hovers" [in Hebrew, "m'sachech", the verb form of "schach"] above them in the aspect of Surrounding Light. Also [it is named thus for the reason that] the numerical value of the word "schach" equals 100, corresponding to the 100 Lights of Zeir Anpin, which descend through it, as was mentioned.

Also, regarding what the Sages have said in the Talmud, Tractate Shabbat, that [a sukkah which is so] thickly covered as to resemble a house - that even though one can't see the stars in it, it is valid retroactively, but ideally the stars should be visible from within [i.e. beneath] the schach: The secret of this is as elaborated upon in our commentaries on the additions to the Shabbat Eve prayers, "Spread upon us the sukkah of Peace"; there it is clarified at great length, the idea that the yesod of Imma becomes spread out like a kind of tent, or sukkah schach, within the body of Zeir Anpin, from the place of his chest, and spreads until the partitions of the body [i.e. his netzach, hod and yesod] - and all the chasadim of the body of Zeir Anpin are above this barrier, for they ascended from below to above, for the barrier is penetrated and they rise. And via these perforations of the schach, and this barrier, these lights descend, and are visible from below via the perforations of this barrier, resembling the stars of the heavens. This is what I heard from my master [the Ari], of blessed memory, at a different time; and it seems not connected to what we said at the beginning [that the schach is at the level of Zeir Anpin's keter, not at his chest level], but this needs in depth investigation.

Translated and adapted from Sefer HaLikutim]