Deuteronomy 17:9-11

17:9 You will go to the Levitical priests and the judge in office in those days and seek a solution; they will render a verdict. 17:10 You must then do as they have determined at that place the Lord chooses. Be careful to do just as you are taught. 17:11 You must do what you are instructed, and the verdict they pronounce to you, without fail. Do not deviate right or left from what they tell you.