It does not apply to [the study of] the order of Hishtalshelut, the chainlike stages of progressive self-screening whereby the Divine light descends from level to level until ultimately this corporeal world is created:

מַה שֶּׁאֵין כֵּן בְּסֵדֶר הַהִשְׁתַּלְשְׁלוּת,

Even if one does comprehend the external aspect of the existence of the sefirot and spiritual levels involved,

אַף אִם מַשִּׂיג הַמְּצִיאוּת,

this is not intrinsically as worthy as the study of the laws of the mitzvot, where one comprehends and grasps their essence.

לֹא עָדִיף מִצַּד עַצְמוֹ כְּלִימּוּד הַמִּצְוֹת שֶׁמַּשִּׂיג וְתוֹפֵס הַמַּהוּת,

Knowledge of the various spiritual levels may indeed be superior for an unrelated reason, namely, that it leads to a “complete heart” (lev shalem), a wholehearted awe of G-d—and this, as the Alter Rebbe will later say, is the purpose of all the mitzvot. Intrinsically, however, gaining this knowledge is not superior to studying the laws governing the performance of the mitzvot, whose essence he can understand.

Moreover, this [study] is considered [in certain cases] the equivalent of actual performance,

וּמַעֲלֶה עָלָיו כְּאִלּוּ קִיֵּים בְּפוֹעַל מַמָּשׁ,

as it is written, “This is the law [of the burnt offering and the meal offering…].”36

כְּמוֹ שֶׁכָּתוּב: "זֹאת הַתּוֹרָה כוּ'".

The Gemara comments on this, “He who occupies himself with these laws is considered as if he had actually offered a burnt offering and a meal offering.”37

Mastering the revealed laws of the commandments is thus in one sense superior to delving into the innermost dimension (the pnimiyut) of the Torah on esoteric subjects such as the order of Hishtalshelut. For the study of the laws relates to the essence of the subject at hand, such as the physical objects with which the commandments are performed.

G-d’s wisdom, moreover, which is inherent in these laws, descends and permeates the physical objects around which the laws revolve. It is thus the essence of G-d’s wisdom that the student comprehends, and thereby, he becomes involved in the “wondrous union” described in the Tanya, Part I, ch. 5, whereby his mortal intellect simultaneously “encompasses and is encompassed by” the Divine wisdom embodied in the Torah which he is studying. This intellectual union in turn unites his soul (which transcends his intellect) with the infinite light that is vested in the wisdom of the Torah.

The above is true only when he understands the essence of his subject. This is the case when he studies (for example) the laws regulating the observance of the commandments. If, by contrast, his subject is the hierarchies of angels in the Worlds of Beriah, Yetzirah, and Asiyah, or, yet higher, the configurations of sefirot within the World of Atzilut, then his grasp is no more than external: he may indeed be aware of his subject’s existence, but he will be unable to know its essence.

Now, all the above notwithstanding, the Alter Rebbe is about to point out the superior aspect of the study of Hishtalshelut.

However, the knowledge of the existence of the Hishtalshelut is also a lofty and exalted mitzvah.38 Indeed, it outweighs them all, all of the mitzvot and the study of their laws in the Torah.

אֶלָּא שֶׁיְּדִיעַת הַמְּצִיאוּת מֵהַהִשְׁתַּלְשְׁלוּת, הִיא גַּם כֵּן מִצְוָה רָמָה וְנִשָּׂאָה, וְאַדְּרַבָּה – עוֹלָה עַל כּוּלָּנָה,

Thus, it is written, “Know this day […that the L-rd is G-d],”39

כְּמוֹ שֶׁכָּתוּב: "וְיָדַעְתָּ הַיּוֹם כוּ'",

and “Know the G-d of your father…”40; i.e., there is an obligation to attain a knowledge or apprehension of Divinity.

"דַּע אֶת אֱלֹקֵי אָבִיךָ כוּ'",

Moreover, this leads to a “whole heart,” for the latter verse concludes, “and serve Him with a whole heart”; i.e., a knowledge of G-d leads one to serve Him with one’s entire being,

וּמְבִיאָה לְ"לֵב שָׁלֵם" כוּ',

As explained in Likkutei Torah, in the discourse beginning V’Lo Tashbit, this refers to serving G-d with awe—and this is the ultimate intent of all the mitzvot, as the Torah states, “G-d has commanded us to perform all these statutes so that we may fear the L-rd our G-d.”41 And it is the study of the innermost dimensions of the Torah and a knowledge of the various spiritual levels which comprise the order of Hishtalshelut that enable one to fulfill the mitzvah of “knowing G-d,” which leads in turn to the “whole heart” of “fearing Him.” Thus, the Alter Rebbe concludes:

And this is the essential thing: the wholehearted awe of G-d is the ultimate purpose of all the commandments.

שֶׁהוּא הָעִיקָּר,

As mentioned above, one can attain this state only through a knowledge of the order of Hishtalshelut, even though this knowledge is merely an awareness of its existence and not a grasp of its essence.

The comprehension of existence entails divesting [this subject] of any physicality….

וְהַשָּׂגַת הַמְּצִיאוּת הוּא לְהַפְשִׁיט מִגַּשְׁמִיּוּת כוּ'.

In other words, one should endeavor to picture its spirituality. Hence, as the Rebbe has often stressed, one should study the innermost and mystical dimension of the Torah in such a way that one “derives sustenance from it”42—viz., the “sustenance” derived from comprehension. And soundly-based comprehension can be secured only when this dimension of the Torah is studied with the intellectual elucidation afforded by the teachings of Chabad.

However, this mitzvah (of knowing G-d and apprehending Divinity) is but one mitzvah of the 613,

רַק שֶׁזּוֹ הִיא מִצְוָה אַחַת מִתַּרְיַ"ג,

and a man must fulfill all 613,

וְהָאָדָם – צָרִיךְ לְקַיֵּים כָּל תַּרְיַ"ג,

for they descend from the essence of the external aspect of the vessels of Atzilut, a source whose standing was explained above.

לְפִי שֶׁהֵן הִשְׁתַּלְשְׁלוּת הַמַּהוּת דְּחִיצוֹנִית דְּכֵלִים דַּאֲצִילוּת,

Hence, one must extensively study all 613 mitzvot and [hence] fulfill them in actual practice in thought, speech, and deed—which parallel Beriah, Yetzirah, and Asiyah respectively—

לְכָךְ, צָרִיךְ לְהַרְבּוֹת בְּלִימּוּד כָּל הַתַּרְיַ"ג וְקִיּוּמָן בְּפוֹעַל מַמָּשׁ בְּמַחֲשָׁבָה דִּבּוּר וּמַעֲשֶׂה, שֶׁהֵן בְּרִיאָה־יְצִירָה־עֲשִׂיָּה,

in order to purify whatever needs purification (beirur) there.

לְבָרֵר בֵּירוּרִין אֲשֶׁר שָׁם.

As previously explained, the extraction and elevation of the sparks exiled in the various worlds is the ultimate purpose of creation.