Deuteronomy 16:18

Judges — Chief magistrates to examine and determine causes and differences. Officers — Who were subordinate to the other to bring causes and persons before him, to acquaint people with the sentence of the judges, and to execute their sentence. Thy gates — Thy cities, which he here calls gates, because there were seats of judgment set. Pursuant to this law, in every town which contained above an hundred and twenty families, there was a court of twenty three judges; in the smaller towns, a court of three judges.