Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 141
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 141, with English translation by Maimonides (Rambam).
להשמיט כספים בשביעית, שנאמר: "שמוט כל בעל משה ידו" (דברים טו,ב).
To remit all financial [obligations] in the seventh year, as [Deuteronomy 15:2] states: "Every creditor must remit...."