הָעַכּוּ"ם וְגֵר תּוֹשָׁב לוִֹין מֵהֶן וּמַלְוִין אוֹתָן בְּרִבִּית שֶׁנֶּאֱמַר (דברים כג כ) "לֹא תַשִּׁיךְ לְאָחִיךָ" לְאָחִיךְ אָסוּר וְלִשְׁאָר הָעוֹלָם מֻתָּר. וּמִצְוַת עֲשֵׂה לְהַשִּׁיךְ לְעַכּוּ"ם שֶׁנֶּאֱמַר (דברים כג כא) "לַנָּכְרִי תַשִּׁיךְ" מִפִּי הַשְּׁמוּעָה לָמְדוּ שֶׁזּוֹ מִצְוַת עֲשֵׂה וְזֶהוּ דִּין תּוֹרָה:
One may lend money to and borrow money from a gentile and a resident alien at interest, as implied by Deuteronomy 23:20: "Do not offer interest to your brother." We may infer: Offering - and taking - interest from "your brother" is prohibited; from people at large, by contrast, it is permitted. It is a positive mitzvah to lend money to a gentile at interest, as Ibid:21 states: "You may offer interest to a gentile." The Oral Tradition teaches that this is a positive commandment. This is the Scriptural Law.
