Deuteronomy 17:9-11

and appear before the cohanim, who are L'vi'im, and the judge in office at the time. Seek their opinion, and they will render a verdict for you.

You will then act according to what they have told you there in that place which ADONAI will choose; you are to take care to act according to all their instructions.

In accordance with the Torah they teach you, you are to carry out the judgment they render, not turning aside to the right or the left from the verdict they declare to you.