Each spark did not descend into this world to perfect itself but to perfect the body and vital soul—as the Alter Rebbe will soon conclude.
וְכָל נִיצוֹץ, לֹא יָרַד לָעוֹלָם הַזֶּה,
Though it is indeed a great descent, a veritable exile for the soul,
אַף שֶׁהִיא יְרִידָה גְדוֹלָה וּבְחִינַת גָּלוּת מַמָּשׁ,
for even if it becomes, in this world, a perfect tzaddik, serving G-d with fear and delighting in an abounding love [of Him],
כִּי גַם שֶׁיִּהְיֶה צַדִּיק גָּמוּר עוֹבֵד ה' בְּיִרְאָה וְאַהֲבָה רַבָּה בְּתַעֲנוּגִים
it will not attain to the quality of its attachment to G-d with fear and love that the soul experienced prior to its descent into this corporeal world nor even [to] a fraction of [its earlier fear and love].
לֹא יַגִּיעַ לְמַעֲלוֹת דְּבֵיקוּתוֹ בַּה' בִּדְחִילוּ וּרְחִימוּ בְּטֶרֶם יְרִידָתוֹ לָעוֹלָם הַזֶּה הַחוּמְרִי, לֹא מִינָּהּ וְלֹא מִקְצָתָהּ,
In fact, there is no comparison or similarity whatsoever between them—between the love and fear of G-d experienced by a soul on earth and that of the soul above, [for] as is obvious to every intelligent man, the body could not bear, etc., a love and fear of such intensity as the soul experienced above in the spiritual realms.
וְאֵין עֵרֶךְ וְדִמְיוֹן בֵּינֵיהֶם כְּלָל, כַּנּוֹדָע לְכָל מַשְׂכִּיל, שֶׁהַגּוּף אֵינוֹ יָכוֹל לִסְבּוֹל כוּ',
Having concluded his comment on the formidable nature of the soul’s descent, the Alter Rebbe returns to his original point: The descent of the soul is not for its own sake—
but its descent into this world, to be clothed in a body and vital soul, is for the sole purpose of perfecting them
אֶלָּא יְרִידָתוֹ לָעוֹלָם הַזֶּה לְהִתְלַבֵּשׁ בַּגּוּף וְנֶפֶשׁ הַחִיּוּנִית, הוּא כְּדֵי לְתַקְּנָם בִּלְבָד,
to separate them from the evil of the three impure kelipot by observing the 365 prohibitions and their “offshoots” i.e., by observing the Biblical and Rabbinic prohibitions,
וּלְהַפְרִידָם מֵהָרָע שֶׁל שָׁלשׁ קְלִיפּוֹת הַטְּמֵאוֹת, עַל יְדֵי שְׁמִירַת שַׁסַ"ה לֹא תַעֲשֶׂה וְעַנְפֵיהֶן,
and to elevate his vital soul, together with the portion of the world at large that relates to it,
וּלְהַעֲלוֹת נַפְשׁוֹ הַחִיּוּנִית עִם חֶלְקָהּ הַשַּׁיָּיךְ לָהּ מִכְּלָלוּת עוֹלָם הַזֶּה,
binding and uniting them with the Ein Sof-light which he draws into them by performing all the 248 positive mitzvot through the agency of the vital soul,
וּלְקַשְּׁרָם וּלְיַיחֲדָם בְּאוֹר־אֵין־סוֹף בָּרוּךְ־הוּא, אֲשֶׁר יַמְשִׁיךְ בָּהֶם עַל יְדֵי קִיּוּמוֹ כָּל רַמַ"ח מִצְוֹת עֲשֵׂה בְּנַפְשׁוֹ הַחִיּוּנִית,
since [the vital soul] is the one that performs all mitzvot involving action, as explained above in ch. 36—that the divine soul can activate the body in performance of the mitzvot only by way of the vital soul.
שֶׁהִיא הִיא הַמְקַיֶּימֶת כָּל מִצְוֹת מַעֲשִׂיּוֹת כַּנִּזְכָּר לְעֵיל.
It is likewise written (in Etz Chaim, Portal 26) that the [divine] soul itself does not need perfecting at all…
וּכְמוֹ שֶׁכָּתוּב [בְּעֵץ חַיִּים שַׁעַר כ"ו], כִּי הַנְּשָׁמָה עַצְמָהּ אֵינָהּ צְרִיכָה תִּיקּוּן כְּלָל כוּ',
and there is no need for it to be embodied in this world in a body and vital soul…except to draw down light to perfect them—the vital soul and the body…
וְלֹא הוּצְרְכָה לְהִתְלַבֵּשׁ בָּעוֹלָם הַזֶּה וְכוּ', רַק לְהַמְשִׁיךְ אוֹר לְתַקְּנָם כוּ',
and this parallels exactly11 the mystery of “the exile of the Shechinah,” whose purpose is to refine the sparks of holiness which fell into the kelipot; so, too, does the divine soul enter into exile within the body and vital soul in order to perfect them and to extract from them the sparks of holiness which they contain.
וְהוּא מַמָּשׁ דּוּגְמַת סוֹד גָּלוּת הַשְּׁכִינָה, לְבָרֵר נִיצוֹצִין וְכוּ'.
The foregoing discussion enables us to understand the particular virtue of mitzvot performed through action:
Creation, and the soul’s descent into the body, were both intended for the purpose of elevating the body and vital soul and thereby the entire world; moreover, this objective is reached primarily through the mitzvot involving action inasmuch as these mitzvot are performed by the body and vital soul; these mitzvot are therefore of primary importance.
Having touched upon the subject of the soul’s descent, however, he adds a parenthetical comment emphasizing the magnitude of this descent. On entering this world, a soul may perhaps attain the loftiest heights of love and fear of G-d that are experienced by a perfect tzaddik—but even this cannot compare to the love and fear that it experienced while in the spiritual worlds before its descent.