Negative commandment · Lo Ta’aseh #235 of 613
Not to lend at interest to a Jew
שלא להלוות בריבית לישראל
The verse · Vayikra 25:37
אֶת־כַּסְפְּךָ לֹא־תִתֵּן לוֹ בְּנֶשֶׁךְ וּבְמַרְבִּית לֹא־תִתֵּן אׇכְלֶךָ
“Thou shalt not give him thy money upon usury, nor lend him thy foodstuffs for increase.”
The Rambam’s words
Not to lend at interest to a Jew, as [Leviticus 25:37] states: "Do not lend him your money at interest."
שלא להלוות בריבית לישראל, שנאמר "את כספך--לא תיתן לו, בנשך" (ויקרא כה,לז).
Why · Sefer HaChinuch #343
To not lend with interest to an Israelite
“It is from the roots of this commandment [that it is] because the good G-d desired the settlement of His people which He chose. And therefore He commanded to remove the obstacle from their path, that one should not swallow up the wealth of his friend without his [even] feeling it, until he finds his house empty of all good.”
Who & when
“And [it] is practiced in every place and at all times by males and females.”
Where in the Mishneh Torah
Hilchot Creditor and Debtor הלכות מלווה ולווה