If a prophet or someone who has dreams arises among you and proclaims a sign or wonder to you, and that sign or wonder he has promised you comes about, but he says, ‘Let us follow other gods,’ which you have not known, ‘and let us worship them,’ do not listen to that prophet’s words or to that dreamer. For the LORD your God is testing you to know whether you love the LORD your God with all your heart and all your soul. You must follow the LORD your God and fear Him. You must keep His commands and listen to His voice; you must worship Him and remain faithful to Him.

 - Deuteronomy 13:1-4, HCSB