Deuteronomy.
Chapter 13.
Maybe a prophet or someone who has dreams about the future will come along and give you a prediction about some sign or miracle, 
and the sign or wonder happens. If after that they tell you, “Let's follow other gods that you don't know, and let's worship them,” 
then you must not listen to what that prophet or dreamer has to say because the Lord your God is trying to find out whether you really love him with all your mind and with all your being. 
You are to follow the Lord your God and respect him. Keep his commandments and do what he says; worship him and hold onto him. 
These kinds of prophets or dreamers must be executed, because they have promoted rebellion against the Lord your God, who led you out of Egypt and rescued you from the prison-house of slavery. They have tried to lead you from the way that the Lord your God has ordered you to follow. You must eliminate the evil among you. 
Even if your own brother, or your son or daughter, or the wife you love, or your best friend secretly encourages you, saying, “Let's go and worship other gods” unfamiliar to you and your forefathers, 
the gods of the nations around you (whether they live close by or far away, in any direction), 
don't give into them or listen to them. Show them no mercy. Don't spare them or protect them. 
No, you absolutely must kill them! You start killing them, and then have everyone else help. 
Stone the person to death for trying to lead you away from the Lord your God, who led you out of Egypt, out of the prison-house of slavery. 
Then every Israelite will hear about it and be afraid, and won't ever do such an evil thing among you. 
It may happen that once you're living in the towns the Lord your God is giving you, you hear 
that evil people have taken over in one of your towns and have led the people there astray, telling them, “Let's go and worship other gods” that you don't know. 
If this does happen you need to make a full investigation, inquiring about the facts and interrogating witnesses. If it's proved beyond doubt that this awful sin has actually been committed among you, 
then you have to kill the people living in that town with the sword. Set apart for destruction its people and its livestock. 
You must pile up all the people's possessions in the middle of the public square, and completely burn the town and everything in it as a complete burnt offering to the Lord your God. The town must remain a heap of ruins forever. It must never be rebuilt. 
Don't take for yourselves anything that has been set apart for destruction so that the Lord won't be angry any more. He will be merciful to you, showing you compassion, and giving you many descendants as he promised to your forefathers, 
because you are obeying the Lord your God, keeping all his commandments that I'm giving you today, and doing what is right in the sight of the Lord your God. 
