Deuteronomy 13:1-3

If ever you have among you a prophet or a dreamer of dreams and he gives you a sign or a wonder, And the sign or the wonder takes place, and he says to you, Let us go after other gods, which are strange to you, and give them worship; Then give no attention to the words of that prophet or that dreamer of dreams: for the Lord your God is testing you, to see if all the love of your heart and soul is given to him.