The Alter Rebbe explains that the purpose of creation is that divine light be revealed within the lowest world. This gives penimiyut a cosmic meaning: the hidden inner vitality of Torah and godliness is meant to become present within ordinary embodied life.
וְהִנֵּה, תַּכְלִית הִשְׁתַּלְשְׁלוּת הָעוֹלָמוֹת וִירִידָתָם מִמַּדְרֵגָה לְמַדְרֵגָה – אֵינוֹ בִּשְׁבִיל עוֹלָמוֹת הָעֶלְיוֹנִים, הוֹאִיל וְלָהֶם יְרִידָה מֵאוֹר פָּנָיו יִתְבָּרֵךְ, אֶלָּא הַתַּכְלִית הוּא עוֹלָם הַזֶּה הַתַּחְתּוֹן, שֶׁכָּךְ עָלָה בִּרְצוֹנוֹ יִתְבָּרֵךְ, לִהְיוֹת נַחַת רוּחַ לְפָנָיו יִתְבָּרֵךְ, כַּד אִתְכַּפְיָא סִטְרָא אָחֳרָא וְאִתְהַפֵּךְ חֲשׁוֹכָא לִנְהוֹרָא – שֶׁיָּאִיר אוֹר ה׳ אֵין־סוֹף בָּרוּךְ־הוּא בִּמְקוֹם הַחֹשֶׁךְ וְהַסִּטְרָא אָחֳרָא שֶׁל כָּל עוֹלָם הַזֶּה כּוּלּוֹ, בְּיֶתֶר שְׂאֵת וְיֶתֶר עֹז וְיִתְרוֹן אוֹר מִן הַחֹשֶׁךְ, מֵהֶאָרָתוֹ בְּעוֹלָמוֹת עֶלְיוֹנִים, שֶׁמֵּאִיר שָׁם עַל יְדֵי לְבוּשִׁים וְהֶסְתֵּר פָּנִים, הַמַּסְתִּירִים וּמַעֲלִימִים אוֹר־אֵין־סוֹף בָּרוּךְ־הוּא שֶׁלֹּא יִבָּטְלוּ בִּמְצִיאוּת. וְהַיְינוּ, מִפְּנֵי גִּילּוּי רְצוֹנוֹ יִתְבָּרֵךְ בַּעֲשֶׂרֶת הַדִּבְּרוֹת, שֶׁהֵן כְּלָלוּת הַתּוֹרָה, שֶׁהִיא פְּנִימִית רְצוֹנוֹ יִתְבָּרֵךְ וְחָכְמָתוֹ, וְאֵין שָׁם הֶסְתֵּר פָּנִים כְּלָל, כְּמוֹ שֶׁנֶּאֱמַר: ״כִּי בְאוֹר פָּנֶיךָ נָתַתָּ לָּנוּ תּוֹרַת חַיִּים״. וְלָכֵן הָיוּ בְּטֵלִים בִּמְצִיאוּת מַמָּשׁ, כְּמַאֲמַר רַבּוֹתֵינוּ־זִכְרוֹנָם־לִבְרָכָה ״שֶׁעַל כָּל דִּבּוּר פָּרְחָה נִשְׁמָתָן כוּ׳, אֶלָּא שֶׁהֶחֱזִירָהּ הַקָּדוֹשׁ־בָּרוּךְ־הוּא לָהֶן בְּטַל שֶׁעָתִיד לְהַחֲיוֹת בּוֹ אֶת הַמֵּתִים״, וְהוּא טַל תּוֹרָה שֶׁנִּקְרָא ״עוֹז״, כְּמַאֲמַר רַבּוֹתֵינוּ־זִכְרוֹנָם־לִבְרָכָה: ״כָּל הָעוֹסֵק בַּתּוֹרָה – טַל תּוֹרָה מְחַיֵּיהוּ כוּ׳״. רַק שֶׁאַחַר כָּךְ גָּרַם הַחֵטְא וְנִתְגַּשְּׁמוּ הֵם וְהָעוֹלָם, עַד עֵת קֵץ הַיָּמִין, שֶׁאָז יִזְדַּכֵּךְ גַּשְׁמִיּוּת הַגּוּף וְהָעוֹלָם, וְיוּכְלוּ לְקַבֵּל גִּילּוּי אוֹר ה׳, שֶׁיָּאִיר לְיִשְׂרָאֵל עַל יְדֵי הַתּוֹרָה שֶׁנִּקְרֵאת ״עוֹז״. וּמִיִּתְרוֹן הַהֶאָרָה לְיִשְׂרָאֵל – יַגִּיהַּ חשֶׁךְ הָאוּמּוֹת גַּם כֵּן, כְּדִכְתִיב: ״וְהָלְכוּ גוֹיִם לְאוֹרֵךְ וְגוֹ׳״, וּכְתִיב: ״בֵּית יַעֲקֹב לְכוּ וְנֵלְכָה בְּאוֹר ה׳״, וּכְתִיב: ״וְנִגְלָה כְּבוֹד ה׳, וְרָאוּ כָל בָּשָׂר יַחְדָּיו וְגוֹ׳״, וּכְתִיב: ״לָבוֹא בְּנִקְרֹת הַצּוּרִים וּבִסְעִיפֵי הַסְּלָעִים מִפְּנֵי פַּחַד ה׳ וַהֲדַר גְּאוֹנוֹ וְגוֹ׳״, וּכְמוֹ שֶׁאוֹמְרִים: ״וְהוֹפַע בַּהֲדַר גְּאוֹן עוּזֶּךָ עַל כָּל יוֹשְׁבֵי תֵבֵל אַרְצֶךָ וְגוֹ׳״:
Clearly, the purpose of the hishtalshelut of the worlds and their descent, degree by degree, is not for the sake of the higher worlds, because for them this is a descent from the light of His Countenance, blessed be He. But the ultimate purpose [of creation] is this lowest world, for such was His will, blessed be He, that He shall have satisfaction when the sitra achara is subdued and the darkness is turned to light, so that the Divine light of the En Sof, blessed is He, shall shine forth in the place of the darkness and sitra achara throughout this world, all the more strongly and intensely, with the excellence of light emerging from darkness, than its effulgence in the higher worlds, where it shines through “garments” and in concealment of the Countenance, which screen and conceal the light of the En Sof, blessed is He, in order that they should not dissolve out of existence. This was so because of the revelation of His will, blessed be He, in the Decalogue constituting the epitome of the whole Torah, which is His innermost will, blessed be He, and His wisdom, wherein there is no concealment of the Countenance at all, as is written, “For by the light of Your Countenance You gave us the Torah of life.” Therefore they [the Israelites at Sinai] repeatedly expired out of existence, as the Rabbis have taught that at each [Divine] utterance their souls took flight…but the Holy One, blessed is He, restored it to them with the dew with which He will revive the dead. This is the dew of the Torah which is called “might,” as the Rabbis have said, “Everyone who occupies himself with the Torah is revived by the dew of the Torah….” Later, however, the sin [of the Golden Calf] caused both them and the world to become gross again—until the end of days, when the dross of the body and of the world will be purified, and they will be able to apprehend the revealed Divine light which will shine forth to Israel by means of the Torah, called “might.” And, as a result of the overflow of the illumination on Israel, the darkness of the gentiles will also be lit up, as is written, “And the nations shall walk by your light…,” and, “House of Jacob, come, let us walk in the light of the L–rd,” again, “And the glory of the L–rd will be revealed, and together all flesh will see…,” and, “To go into the holes of the rocks, and into the clefts of the boulders, for fear of the L–rd and for the glory of His majesty.” And as we pray, “Reveal Yourself in the majesty of Your glorious might over all the inhabitants of Your terrestrial world….”
