The distinction between [causing a Divine] indwelling (by collective study) and the allotment of a reward (to an individual student) is understood by discerning thinkers.

וְהַהֶפְרֵשׁ שֶׁבֵּין הַשְׁרָאָה לִקְבִיעוּת שָׂכָר מוּבָן לִמְבִינֵי מַדָּע,

For the allotment of a reward is what takes place when G-d illuminates “the soul that seeks Him”21 with the light of His Torah, which is truly the covering in which G-d garbs Himself.

כִּי, קְבִיעַת שָׂכָר הוּא – שֶׁמֵּאִיר ה' "לְנֶפֶשׁ תִּדְרְשֶׁנּוּ", בְּאוֹר תּוֹרָתוֹ, שֶׁהוּא מַעֲטֵה לְבוּשׁוֹ מַמָּשׁ,

Through this garment, i.e., through the Torah, G-d illuminates the soul of the Jew who seeks Him. This search for Him can take place either during the service of prayer that precedes one’s study of Torah or during one’s actual study. As explained at the conclusion of ch. 37 of the Tanya, the Talmudic phrase קוֹרֵא בַּתּוֹרָה can mean not only “reading (i.e., studying) the Torah” but also “calling [G-d] through the Torah.” In this sense, when one studies Torah, one resembles a child who calls his father, asking him to come and be with him.

For this reason, the Torah is called “light,” as it is written,22 “He garbs Himself in light, as with a garment.”23

וְלָכֵן נִקְרֵאת הַתּוֹרָה "אוֹר", שֶׁנֶּאֱמַר: "עוֹטֶה אוֹר כַּשַּׂלְמָה",

This verse refers to the degree of illumination (diffused by the Torah) which, like a garment, is finite.

Likewise, the faculties of the soul are inherently limited, both quantitatively and qualitatively. Since the light that emanates to the soul must be integrated within its faculties, this illumination itself must also be limited. In the words of the Alter Rebbe:

Now, the soul is limited and finite in all its faculties.

וְהַנֶּפֶשׁ הִיא בַּעֲלַת גְּבוּל וְתַכְלִית בְּכָל כֹּחוֹתֶיהָ,

Therefore, the light of G-d that radiates in it is also limited and contracted and vests itself within it.

לָכֵן גַּם אוֹר ה' הַמֵּאִיר בָּהּ הוּא גְבוּלִי, מְצוּמְצָם, וּמִתְלַבֵּשׁ בְּתוֹכָהּ,

This is why the hearts of those who seek G-d are ecstatically aroused at the time of prayer and the like.

וְעַל כֵּן יִתְפָּעֵל לֵב מְבַקְשֵׁי ה' בִּשְׁעַת הַתְּפִלָּה וְכַיּוֹצֵא בָהּ,

For their hearts rejoice in Him and exult “even with exultation and song,”24

כִּי בוֹ יִשְׂמַח לִבָּם, וְיָגִיל "אַף גִּילַת וְרַנֵּן",

and their souls delight in the pleasantness of G-d25 and His light

וְתִתְעַנֵּג נַפְשָׁם בְּנוֹעַם ה' [נוסח אחר: עַל ה'] וְאוֹרוֹ,

as it becomes revealed through the covering in which [G-d] garbs Himself, which is the Torah;

בְּהִגָּלוֹתוֹ מִמַּעֲטֵה לְבוּשׁוֹ שֶׁהִיא הַתּוֹרָה,

“and His arrow comes forth like lightning”26: from this garment, this illumination initially emanates to the soul with all the vigor of a lightning bolt.27

וְיָצָא כַבָּרָק חִצּוֹ,

This is the allotment of the reward for the [study of] Torah, which is always fixed in the soul that labors in it.

וְזוֹ הִיא קְבִיעַת שְׂכַר הַתּוֹרָה, הַקְּבוּעָה תָּמִיד בְּנֶפֶשׁ עֲמֵלָה בָּהּ.

Being fixed within the soul constantly, this reward is received by the soul not only in the World to Come—when the soul is enabled to apprehend rewards that are not to be obtained in this world28—but in this world as well. And since this kind of reward consists of a finite degree of illumination, it can be received by the soul even as the soul finds itself within the body.

This is why it is written that a reward awaits even one individual who studies Torah.