On this site the writer, who goes by inagreement1, states that the two reasons people say that you can't use the bible to prove that god's real is that they don't read the bible or that they don't believe in the bible. Which to put simply is stupid.
I haven't read the Harry Potter series but I'm a hundred percent positive that the presence of those books does not prove the existence of a wizard boy named Harry. In fact if you apply this logic to the Harry Potter series it would prove that Harry Potter is more real than your god because there are more books. Just cause there is a book abut it doesn't prove it's real. It's like saying that Mario Kart proves that Mario is real and races his friends around a colorful track.
Moving on the his second point -If one can even call it that.- that "they don't believe in the bible." Let's just take a moment and let the pain of the ignorance pass. Okay. inagreement1, that's not why we say this. We say it because it's circular logic. Meaning when we ask "How do you know the bibles true?" we get "Because it says so." Which isn't evidence to it's truth.
If you don't understand this simple concept then you don't even need to try to be "proving" anything. Not even that you poop. Not even something as simple as that. Ever.