A popular method of debate especially when engaging christians is to use the sillyness in thier holybooks against them. I normally shy away from this unless I have some kind of understaning of what type of godbotherer I'm dealing with.
There is sometimes a time constraint and a long disscussion is not possable. My main goal when talking with the faithful ( or really delusional) is trying to engage thier minds, cause them to think and think outside of thier holybooks.
My three best (favorite) nonscriptural questions / statements to make the the faithful think.
1. How does heaven work ? If you are a good christian when you die you will go there.But what if a loved one wasn't ? How could you be happy in paradise when say ,your son' is burning in hell.
2.If god is perfect why Does he have so many human trates? Anger,jealousy,vengence , if I am to believe in a god I'd expect better in a perfect being
3. You tell me god wants to have a relationship with me. Why does the master of the universe ,the creator of all things have wants? A perfect being should be lacking for nothing.
What are your best Ideas to make the religious think? I'm always looking for more ammunition.