If there is no God, the Bible is and INCREDIBLE hoax. The hoax is not the existence of God, but man's perversion of the Word, or message of God. The hoax is that God's Word surely was supposed to provide a guide for moral living, and thru out history "religion" has been used to justify all kinds of "unholy" things.
Today the perversion continues with some claiming divine superiority because the are saved, the rest are doomed, and others calling everyone else "infidels" or "enemies of God" - including the saved.... You can draw your only conclusions....
Personally, I don't know how someone could not believe in God, but that's me....And I have no idea if what I believe about God is right or wrong, but I believe we all have moral obligation to do our best for ourselves, and others..... We are all free to believe as we see fit....