What about the morals of those who don't share your belief in "God" what do you think makes them not do those things?
Because as created beings, they still reflect the eternal law of the Creator, which is why certain ethics such as "don't kill" and "don't steal" are generally held in common.
Read the links that I provided in my previous post. That should answer most questions about where natural law theory comes from.
I mean no disrespect to those who follow the Bible faithfully, I just have my own way of understanding and believeing in "God", which I am sure differs from everyone here. I also believe that those who choose to hide behind the Bible aren't seeking any truth, in fact they may be running from it, to disprove anything written in the Bible will surely cast doubt on what is remaining.