9 where you shall consult with the levitical priests and the judge who is in office in those days; they shall announce to you the decision in the case. 10 Carry out exactly the decision that they announce to you from the place that the Lord will choose, diligently observing everything they instruct you. 11 You must carry out fully the law that they interpret for you or the ruling that they announce to you; do not turn aside from the decision that they announce to you, either to the right or to the left. 12 As for anyone who presumes to disobey the priest appointed to minister there to the Lord your God, or the judge, that person shall die. So you shall purge the evil from Israel.
Matthew Henry's Commentary on Deuteronomy 17:9-12
Commentary on Deuteronomy 17:8-13
(Read Deuteronomy 17:8-13)
Courts of judgment were to be set up in every city. Though their judgment had not the Divine authority of an oracle, it was the judgment of wise, prudent, experienced men, and had the advantage of a Divine promise.