Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 28
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 28, with English translation by Maimonides (Rambam).
שלא לשמוע למתנבא בשם עבודה זרה, שנאמר "לא תשמע, אל דברי הנביא" (דברים יג,ד).
Not to listen to someone who prophesies in the name of false gods, as [Deuteronomy 13:4] states: "Do not listen to the words of that prophet."