The Alter Rebbe explains that the purpose of creation is the revelation of Godliness within the lower world; this supplies a Chabad framework for penimiyut as inner revelation rather than surface appearance.
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. וְגַם כְּבָר הָיָה לְעוֹלָמִים מֵעֵין זֶה, בִּשְׁעַת מַתַּן תּוֹרָה, כְּדִכְתִיב: ״אַתָּה הָרְאֵתָ לָדַעַת כִּי ה׳ הוּא הָאֱלֹהִים אֵין עוֹד מִלְּבַדּוֹ״ – ״הָרְאֵתָ״ מַמָּשׁ, בִּרְאִיָּה חוּשִׁיִּית, כְּדִכְתִיב: ״וְכָל הָעָם רוֹאִים אֶת הַקּוֹלוֹת״ – ״רוֹאִים אֶת הַנִּשְׁמָע״, וּפֵירְשׁוּ רַבּוֹתֵינוּ־זִכְרוֹנָם־לִבְרָכָה: מִסְתַּכְּלִים לַמִּזְרָח וְשׁוֹמְעִין אֶת הַדִּבּוּר יוֹצֵא אָנֹכִי כוּ׳. וְכֵן לְאַרְבַּע רוּחוֹת וּלְמַעְלָה וּלְמַטָּה, וְכִדְפֵירְשׁוּ בַּתִּיקּוּנִים ״דְּלֵית אֲתַר דְּלָא מַלֵּיל מִינֵּיהּ עִמְּהוֹן כוּ׳״. 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׳״.
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. Something of this revelation has already been experienced on earth, at the time of the Giving of the Torah, as is written, “You have been shown to know that the L–rd is G–d; there is none else aside from Him”—“have been shown” verily with physical vision, as is written, “And all the people saw the thunderings”—“they saw what is [normally] heard.” And the Rabbis, of blessed memory, explained, “They looked eastward and heard the speech issuing forth: ‘I am,’ etc., and so [turning] toward the four points of the compass, and upward and downward,” as is also explained in the Tikkunim that “There was no place from which He did not speak to them….” 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….”