I read a couple pages of responses, and if someone brought this up, forgive me. But you could point out the many contradictions and outright scientific errors in the Bible. If you don't want to read it, google is invaluable. So is the Skeptic's Bible. Believers will retort that while the book was written by men and may contain some flaws because they wrote from a less enlightened age, the general message was inspired by God and still holds true: that of the forgiving power and salvation of Jesus. You can still suggest why the book that supposedly is the most important one ever written was cobbled together so sloppily. You could suggest that you yourself could have written a more moral book. You could ask how an all-powerful God could possibly have allowed such an account to be his ultimate message for mankind. Couldn't he have insured without a shadow of a doubt that it was timely and scientifically accurate and free from self-contradiction? Surely this wouldn't have been a hard task for a being that hung the stars. Or, if an account from people just after Christ was absolutely essential, he could have, with his omniscience, updated different writers down through the ages and with each generation, issued an updated account as times have changed. He could have explained why he allowed slavery to take place on his watch, the witch trials, the Holocaust and the rest of it. He could have explained why he created us knowing full well the entire ugly business of humankind and sin coming into the world before it happened. He could have answered the basic question: Why bother in the first place?
Just some thoughts. Good luck.
Just some thoughts. Good luck.