Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 194
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 194, with English translation by Maimonides (Rambam).
להשיב את הגזל, שנאמר: "והשיב את הגזילה אשר גזל" (ויקרא ה,כג).
To return a stolen object, as [Leviticus 5:23] states: "And he shall return the object which he stole."