Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 246
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 246, with English translation by Maimonides (Rambam).
לדון בדין טוען וכופר, שנאמר: "על כל דבר פשע" (שמות כב,ח).
To render judgment [in questions] regarding claims made by one person against another, as [Exodus 22:8] states: "For every matter of trespass, concerning an ox, concerning a donkey, or concerning a sheep...."