"The poor man with you" — the Holy One, blessed be He, said: Know that I am the One who made him poor and you rich, and I am able to turn you back and make you poor. Rav Nachman said: What is written? "You shall surely give to him," and it does not say here "because for the sake of," but rather "because on account of this thing" (Deuteronomy 15:10). It is a wheel: I made you rich and him poor; do not cause Me to turn the wheel back and make you poor. See what is written: "You shall not harden your heart from your brother, the needy one" — it does not say here "from the poor man" but "from your brother," for the two of you are equal.
The Wheel That Turns Between the Rich Man and the Poor
Yalkut Shimoni on Torah 350:4
אֶת הֶעָנִי עִמָּךְ, אֲמַר הַקָּדוֹשׁ בָּרוּךְ הוּא, הֱוֵי יוֹדֵעַ שֶׁאֲנִי שֶׁעָשִׂיתִי אוֹתוֹ עָנִי וּלְךָ עָשִׁיר, יָכוֹל אֲנִי לְהַחֲזִירְךָ לַעֲשׂוֹתְךָ עָנִי. אֲמַר רַב נַחְמָן, מַה כְּתִיב, "נָתוֹן תִּתֵּן לוֹ", "כִּי לְמַעַן" אֵין כְּתִיב כָּאן, אֶלָּא (שם) "כִּי בִּגְלַל הַדָּבָר הַזֶּה", גַּלְגַּל הוּא, אֲנִי עָשִׂיתִי אוֹתְךָ עָשִׁיר וְאוֹתוֹ עָנִי, אַל תִּגְרֹם לִי שֶׁאַחֲזִיר אֶת הַגַּלְגַּל וְאֶעֱשֶׂה אוֹתְךָ עָנִי, רְאֵה מַה כְּתִיב, "לֹא תְאַמֵּץ אֶת לְבָבְךָ מֵאָחִיךָ הָאֶבְיוֹן", "מֵעָנִי" אֵין כְּתִיב כָּאן אֶלָּא "מֵאָחִיךָ", שֶׁשְּׁנֵיכֶם שָׁוִין.