Positive commandment · Mitzvat Aseh #197 of 613
To lend to the poor
להלוות לעני
The verse · Shemot 22:24
אִם־כֶּסֶף תַּלְוֶה אֶת־עַמִּי אֶת־הֶעָנִי עִמָּךְ לֹא־תִהְיֶה לוֹ כְּנֹשֶׁה לֹא־תְשִׂימוּן עָלָיו נֶשֶׁךְ
“If thou lend money to any of my people that is poor by thee, thou shalt not be to him as a creditor, neither shall you lay upon him interest.”
The Rambam’s words
To lend to the poor, as [Exodus 22:24] states: "If you will lend money to my people...." In this instance, the word "if" does not refer to a matter left to one's volition, but to a commandment, as [Deuteronomy 15:8] states: "You shall surely lend him."
להלוות לעני, שנאמר: "אם כסף תלווה את עמי" (שמות כב,כד); "אם" זה אינו רשות אלא מצוה, שנאמר: "והעבט, תעביטנו" (דברים טו,ח).
Why · Sefer HaChinuch #66
Lending to the poor person
“The root of the commandment is that G-d wanted His creations to be trained and habituated to the trait of kindness and of mercy, since it is a praiseworthy trait.”
Where in the Mishneh Torah
Hilchot Creditor and Debtor הלכות מלווה ולווה