Method 1: Tell him you don't agree with him. Then follow it up with explaining why everything he believes in is all a crock of nonsense invented by a cult of bronze-age savages if you're harsh, debunk his claims, one by one if intermediate and if you're gentle, just try to persuade him that nothing he can say can convince you to believe what he does:
A few weeks ago a bible thumper came to my door and said that fish fossils were found at the tops of mountains and that it proves that there was a great flood. I told him that is the result of continental drift and that they are hundreds of millions of years old and not only don't prove there was a worldwide flood thousands of years ago but prove that the world is at least 100 thousand times as old as he says. He then said that they dated to only a few thousand years ago. I in turn told him that if he tries to use radioisotope dating to convince me that the universe is 6000 years old, that he has lost the argument before he even began it.
Pros: you'll feel superior
Cons: You're going to end up arguing for a really long time
Method 2: Nod your head and agree with him
Have you accepted Jesus as your savior?
Say "uh huh" and nod your head.
Pros: potentially get rid of him fast.
Cons: Somewhat humiliating. Can backfire especially if he then asks followup questions and tries to get you to join his bible study group.
Method 3: Put a door knocker on your door that looks like male genitalia.
Pros: Bible thumpers may decline to knock on your door in the first place.
Cons: Your neighbors and the mailman may suspect you of being a child molester. Except that neighbor up the hill who drives the Prius with rainbows painted all over it. He'll probably ask you on a date.
Their actions usually do more harm than good to their cause and bring into disrepute and ridicule those more reticent Christians.
He thinks everything in the bible should be taken literally; he's a foolish bible thumper.
See George W. Bush, John Ashcroft, Jerry Falwell, Pat Robertson, right-wing nutjob
often characterized by their constant refences to the bible and their intent on converting everyone in a 100 mile radius.
They are essentially the same as Islamic fundamentalists, with the same religous zeal and fantacism.
"Hands that help are far better than lips that pray."
bible thumper:you cant watch south park!its against christianity!!your going to hell!
me:dude, where does it say in the bible i cant watch a tv show?