If there appears among you a prophet or a dream-diviner—and he gives you a sign or a portent, and the sign or portent that he named to you comes true—saying, “Let us follow other gods—whom you have not known—and worship them,” do not heed the words of that prophet or that dream-diviner. For YHWH your God is testing you to see whether you really love YHWH your God with all your heart and soul.

Deuteronomy 13, 2-4