Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 236
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 236, with English translation by Maimonides (Rambam).
להיות החובל משלם ממון, שנאמר: "וכי יריבון אנשים--והכה איש" (שמות כא,יח).
For a person who injures [a colleague] to pay him damages, as [Exodus 21:18] states: "If men will quarrel and one man will strike [his colleague]...."