Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 176
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 176, with English translation by Maimonides (Rambam).
למנות שופטים ושוטרים בכל קהל וקהל מישראל, שנאמר: "שופטים ושוטרים, תיתן לך" (דברים טז,יח).
To appoint judges and court officers in each and every Jewish community, as [Deuteronomy 16:18] states: "Appoint judges and court officers...."