Deuteronomy 13:1-5
13:1 Suppose a prophet or one who foretells by dreams should appear among you and show you a sign or wonder,
13:2 and the sign or wonder should come to pass concerning what he said to you, namely, “Let us follow other gods” – gods whom you have not previously known – “and let us serve them.”
13:3 You must not listen to the words of that prophet or dreamer, for the Lord your God will be testing you to see if you love him with all your mind and being.
13:4 You must follow the Lord your God and revere only him; and you must observe his commandments, obey him, serve him, and remain loyal to him.
13:5 As for that prophet or dreamer, he must be executed because he encouraged rebellion against the Lord your God who brought you from the land of Egypt, redeeming you from that place of slavery, and because he has tried to entice you from the way the Lord your God has commanded you to go. In this way you must purge out evil from within.