I don't know how we can differentiate what is good and bad without a God, because we will not have a basis. If we will depend on our own views of what is good and evil, then goodness will vary from one person to another which is ofcourse biased by personal beliefs and cultural background. If we try to broaden our undersranding to other beliefs, then everything will be called "good" in the end, which may not make sense.
It's called philosophy... many have tried it in the past... you can try it too
Let's start with Immanuel Kant's Universalized Maxim:
"What if everybody did that?"
Example 1, Murder... What if everybody did that?
Answer: Everyone dies highlander style as society crumbles... ergo, murder is bad... mkay?
All this is possible without god... I don't need some dusty book to tell me murder is bad... I can figure that out on my own, its quite simple
Besides the fact that relying on the bible for moral guidance, as others have pointed out, can end up with you in prison... the bible commands its followers to murder people for all sorts of reasons (rape, unruly children, witches, homosexuals, other religions, etc)... if you follow the bible literally, you WILL go to prison... that is NOT good moral guidance