The Alter Rebbe discusses the purpose of ordinary action in a world made for divine dwelling, a framework often used to explain that bitachon works through natural channels rather than by bypassing them.
וְהִנֵּה, מוּדַעַת זֹאת מַאֲמַר רַבּוֹתֵינוּ־זִכְרוֹנָם־לִבְרָכָה, שֶׁתַּכְלִית בְּרִיאַת עוֹלָם הַזֶּה הוּא – שֶׁנִּתְאַוָּה הַקָּדוֹשׁ־בָּרוּךְ־הוּא לִהְיוֹת לוֹ דִּירָה בַּתַּחְתּוֹנִים. 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. וְלָזֶה נָתַן הַקָּדוֹשׁ־בָּרוּךְ־הוּא לְיִשְׂרָאֵל אֶת הַתּוֹרָה, שֶׁנִּקְרֵאת עוֹז וְכֹחַ, וּכְמַאֲמַר רַבּוֹתֵינוּ־זִכְרוֹנָם־לִבְרָכָה, שֶׁהַקָּדוֹשׁ־בָּרוּךְ־הוּא נוֹתֵן כֹּחַ בַּצַּדִּיקִים לְקַבֵּל שְׂכָרָם לֶעָתִיד לָבֹא, שֶׁלֹּא יִתְבַּטְּלוּ בִּמְצִיאוּת מַמָּשׁ בְּאוֹר ה׳ הַנִּגְלֶה לֶעָתִיד בְּלִי שׁוּם לְבוּשׁ, כְּדִכְתִיב: ״וְלֹא יִכָּנֵף עוֹד מוֹרֶיךָ [פֵּירוּשׁ, שֶׁלֹּא יִתְכַּסֶּה מִמְּךָ בְּכָנָף וּלְבוּשׁ], וְהָיוּ עֵינֶיךָ רוֹאוֹת אֶת מוֹרֶיךָ״, וּכְתִיב: ״כִּי עַיִן בְּעַיִן יִרְאוּ וְגוֹ׳״, וּכְתִיב: ״לֹא יִהְיֶה לָּךְ עוֹד הַשֶּׁמֶשׁ לְאוֹר יוֹמָם וְגוֹ׳, כִּי ה׳ יִהְיֶה לָּךְ לְאוֹר עוֹלָם וְגוֹ׳״.
It is a well-known Rabbinic statement that the purpose of the creation of this world is that the Holy One, blessed is He, desired to have an abode in the lower worlds. 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. For this purpose, the Holy One, blessed is He, gave to Israel the Torah which is called “might” and “strength,” as the Rabbis, of blessed memory, have said that the Almighty puts strength into the righteous in order that they may receive their reward in the hereafter, without being nullified in their very existence, in the Divine light that will be revealed to them in the hereafter without any cloak, as is written, “Your teacher shall no longer be concealed from you [literally: He will not conceal Himself from you with robe and garment]…but your eyes shall see your Teacher.” It is also written, “For they shall see eye to eye…” and “You shall no longer have the sun for light by day…for the Lord shall be to you for an everlasting light….”