As Divided for a Leap Year
Tanya for 26 Elul
But it is plain and clear to all, that there is a great difference between the apprehension of the Kabbalists, such as R. Shimon bar Yochai and R. Isaac Luria, of blessed memory, which is an apprehension through wisdom and knowledge, and the prophetic apprehension  of Moshe Rabbeinu, peace to him, and the other prophets, to which Scripture refers as actual vision. [Seeing something grasps its essence; comprehension merely grasps its externality.
In these terms Scripture describes Moshe Rabbeinu's prophetic apprehension: ] "You shall see My back." [Likewise even with Isaiah, a lesser prophet than Moshe Rabbeinu, who was the greatest of prophets: ] "And I saw G-d." [Furthermore, even before G-d gave the Torah we find Abraham's prophecy referred to in these terms:  ] "And G-d appeared to him."
Now, though the term ["seeing" with regard to prophecy] is used in a metaphorical sense and does not denote actual sight by the physical, fleshly eye, nevertheless, the analogue needs to resemble the analogy. [Just as the analogy of physical sight means that the viewer beholds the essence of a thing, so too the analogue - prophetic vision - must refer to a spiritual kind of seeing that grasps the essence of the spiritual level that is beheld through prophecy.]
Thus too the Targum translates the above-quoted "vayeira eilav HaShem": "And G-d became revealed  to him...," indicating revelation, meaning that G-d,  blessed be He, being hidden, became manifest to [Abraham.
In this direct mode of revelation, the recipient of the Divine manifestation is able to absorb and internalize it, just as with visual sense-perception. The above-described manner of spiritually "seeing" a revelation is thus quite different from "hearing", an inferior level of perception which leaves the recipient with a less tangible impression.]
It is different, though, with the apprehension of the Kabbalists. G-d, blessed be He, Who is hidden, did not become revealed to them in a manifest mode; rather, they apprehend the secrets of wisdom in a manner  which is hidden and removed from them. [They merely "hear" about these matters rather than truly "see" them.]
[Our Sages] therefore taught that  "A wise man is superior to a prophet," because through his wisdom he can apprehend levels [of Divinity] far higher than those that can descend by means of revelation to prophets in their prophetic vision. 
[Since the revelation of prophecy is "visual", the most sublime levels such as Supernal Chochmah cannot possibly be revealed and "seen" below.] For only the lowest levels can descend and become revealed to [the prophets], namely, the levels of Netzach-Hod-Yesod- Malchut, for it is they that always descend and become revealed from the Emanator to the recipient, in the form of intellectual perception and [creative] life-force.
Thus it is known to the students of Kabbalah  that the Netzach- Hod-Yesod-Malchut [i.e., the lowest levels] of the higher [realm] vest themselves in the lower [realm], in order to animate it.
For they are the conduits of the beneficent flow that bring down the life-force from the higher level to the lower, with respect to all the worlds and levels. Hence they also become revealed to the prophets as an actual revelation, [i.e., as prophecy.]
Within these [four Sefirot] is vested the light of Binah, the attribute which relates to understanding the G-dliness [that emanates] from  the light of the blessed Ein Sof.
And within [Binah] are vested the external aspects of Chochmah, which are a level that transcends the conception and comprehension of Divinity, for the term Chochmah denotes the source of conception and comprehension.
[As explained in Tanya, Part I, ch. 18, the word Chochmah comprises two words: Koach Mah - "the faculty of the unknown,"  for it is a faculty that cannot be grasped intellectually.]
This is why it is stated in the Zohar  that "The Torah derives from Chochmah."
For the reasons for the commandments have not been revealed  [in rational terms]; they transcend conception and comprehension, [i.e., Chochmah.] And even in the occasional places where some apparently intelligible reason has been revealed and explained, this reason alone, which is understandable to us, is not the ultimate and full reason; [we have not yet plummeted its depths;] rather, within [this reason] is vested the innermost core [the pnimiyut] and mystic principle of Chochmah that transcends comprehension and understanding.
[In a public address  the Rebbe Shlita once explained why the Alter Rebbe makes the point that even when we have some intelligible reason for a mitzvah, this is not "Tachlit Ha-Taam." This phrase, rendered above as "the ultimate reason," would more literally mean "the end of the reason"; i.e., the explanation given for a commandment is not the last word in the reason for performing it. Not only does the mitzvah remain in some measure unexplained: even the reason remains in some measure unexplained. For in essence, a mitzvah is a superrational expression of the Divine Will, which is fulfilled through its performance.
At the very beginning of Derech Mitzvotecha (subtitled Sefer Taamei HaMitzvot - "A Book on the Reasons for the Mitzvot"), the Tzemach Tzedek -(the author)- writes similarly  that what one should chiefly keep in mind during the performance of a commandment is the intent of doing it because G-d has so commanded us. The fact that we may not understand just why G-d desired this particular action done, is immaterial.
The Tzemach Tzedek goes on to say that whatever modest insight we may have about the purpose of the mitzvot - according to the Kabbalah and Chassidut, or according to Jewish philosophy (chakirah) and homiletics (derush) - is not even a glimmer of their true intent.
It is a finite drop in an infinite ocean. For no human being, clothed as he is within a corporeal body, can possibly comprehend the infinite domain of spirituality. Even Moshe Rabbeinu, who has experienced more than three thousand years of constant elevation in Gan Eden, advances constantly in his understanding of the rationale underlying the mitzvot.
Concerning these successive levels of comprehension the verse states,  "To every yearning, even to the point of expiry, I have seen an end; Your mitzvah is very wide." I.e., the comprehension and yearning experienced in Gan Eden are finite, whereas a mitzvah defies limitation: the extent of its inner content is endless. 
One outstanding question: Why, though, does the Alter Rebbe write that intelligible reasons have been given only for "occasional" mitzvot, whereas in fact this would appear to apply to a multitude of commandments (of the categories of mishpatim and eduyot), if not to a majority?
Likkutei Biurim on Tanya (by R. Yehoshua Korf) quotes the Rebbe Shlita as answering this question in the following manner: In most cases only a general reason is provided, while the details remain unexplained. For example, while the general reason for the mitzvah of tefillin is stated - that it be  "a sign upon your hand...," no revealed explanation is provided for the myriad details relating to this commandment, such as: why the tefillin must be square; why the four scrolls in the tefillin of the head must be housed in four separate compartments while the Biblical passages in the tefillin of the hand must be inscribed together on one scroll; why the straps of the tefillin must be black; and so on and on.]
The same is true with respect to every word uttered by the mouth of the Holy One, blessed be He, to the prophets, as recorded in the Tanach - [Every word of prophecy found in the Tanach is applicable not only to the generation that first heard them, but to all future generations as well.]  whether they be words of admonition, as transmitted by the prophets, or narratives of incidents.
[An incident is recorded in the Tanach not only as history but also as an eternal message for all generations.] Vested in them - [in these words of rebuke or narrative] - is an aspect of the Divine Chochmah that transcends conception and comprehension.
This is empirically evident from the principle of kri, [the Scriptural text as read], and ktiv, [the Scriptural text as written, the two not always being identical.] The kri reflects the comprehension [of the text] as revealed to us. The ktiv transcends conception and comprehension.
That is, a particular word in its written form has no comprehensible "garment", though as read aloud it does have such a "garment", [i.e., it is readily comprehensible. An example of this would be the verse,  "Know that the L-rd is G-d; He has made us, `velo anachnu,' His people and the sheep of His pasture."
The ktiv form of the word `velo' ends with an "alef," while the kri form of the word ends with a "vav." According to the latter form the verse is readily comprehensible: "Know that the L-rd is G-d; He has made us, `velo anachnu' - and we are His...." In the ktiv form, however, the verse reads, "He has made us and not us...." While this has meaning on a more sublime level,  in the simple sense the ktiv of this verse seems exceedingly difficult to comprehend. 
The same applies to the large letters [that are occasionally found] in the Tanach; they derive from a sublime world - [from the Sefirah of Binah] - and radiate from there openly, and not through a garment like the other letters.
- (Back to text) Shmot 33:23.
- (Back to text) Note of the Rebbe Shlita: In contrast, by means of their [non- prophetic] `apprehension through wisdom and knowledge' they comprehended [higher levels, such as] Keter, and so on.
- (Back to text) Yeshayahu 6:11.
- (Back to text) Bereishit 18:1.
- (Back to text) Heb. text emended above according to the Glosses and Emendations of the Rebbe Shlita.
- (Back to text) The above reading "Ha-ne-lam" could imply that the manner of their apprehension is hidden from them; the variant reading "Be-ne-lam" would imply that the subject of their apprehension is hidden from them.
- (Back to text) Bava Batra 12a.
- (Back to text) Note of the Rebbe Shlita: This is not the case with their comprehension, as [in footnote 13] above.
- (Back to text) Lit., "to those versed in the Hidden Wisdom." In the original text, the three Hebrew words are abbreviated to Lamed Yud Chet, which is an abbreviation for Le Yodei Chein (the letter chet being read as if vocalized with a tzeirei). The letters Chet Nun (alone) in turn are an abbreviation for Chochma Nisteres (Hidden Wisdom).
- (Back to text) According to the variant parenthetical text, "...understanding the G-dliness and the light of the blessed Ein Sof"; i.e., the [infinite] Ein Sof-light too can filter down to the level of mortal understanding.
- (Back to text) Zohar III, 28a.
- (Back to text) Parshat Beshalach, 62a; cf. Parshat Chukat, 182a and Parshat Vaetchanan, 261a; et al.
- (Back to text) Cf. Sanhedrin 21a.
- (Back to text) Shabbat Parshat Vayeishev, 5724.
- (Back to text) P. 4b.
- (Back to text) Tehillim 119:96, explained in Epistle 17, above.
- (Back to text) As an instance of this, consider the commandment involving the nesting bird (Devarim 22:6-7), chosen by the Sages (Berachot 5:3) as a classic example of a mitzvah which one should not assume one knows the reason for. The Rebbe Shlita points out that in Moreh Nevuchim (Vol. III, sec. 48) the Rambam offers an explanation for this mitzvah, yet in his Commentary on the Mishnayot the Rambam himself writes that this is a mitzvah "which has no explanation"!
- (Back to text) Devarim 6:8.
- (Back to text) See Megillah 14a.
- (Back to text) Tehillim 100:3. See also Bereishit Rabbah, beginning of ch. 1.
- (Back to text) Note of the Rebbe Shlita: Zohar I, 120b; Or HaTorah (Yahel Or) of the Tzemach Tzedek on this verse in Tehillim (and see further references there).
- (Back to text) Note of the Rebbe Shlita: But see commentary of Rashi there.