When people quote the bible to non-believers do they realize that most agnostics/atheists don't care what the bible has to say? We don't follow the bible for a reason. You giving me a direct quote is not going to convince me to start believing, ever.
To religious folk - if atheists had a book to which they subscribed that detailed their beliefs and I quoted it to make my point, would it carry any weight with you?
Most times quoting the bible (unless specifically debating passages) comes off as bible thumping or fundamentalist preaching.
This has been your agnostic public service announcement, thank you.