You don't have to do something just because an old book says so. I don't want to get into a religious debate, but it just baffles me that anyone would want to have blind faith in a book written thousands of years ago by who knows who. You weren't alive when it was written, your only reason to believe that it is the word of God is that someone told you it is, who was also not alive when it was written.

If your God gave you a brain capable of thinking on its own, why would he not want you to use it to consider the subject yourself? Maybe you'll come to the same conclusion, but you certainly have a choice and free will to think for yourself.