Deuteronomy 13:1-3

MSB(i) 1 If a prophet or dreamer of dreams arises among you and proclaims a sign or wonder to you, 2 and if the sign or wonder he has spoken to you comes about, but he says, “Let us follow other gods (which you have not known) and let us worship them,” 3 you must not listen to the words of that prophet or dreamer. For the LORD your God is testing you to find out whether you love Him with all your heart and with all your soul.