Ever read The Code of Hammurabi?
written almost 2k years before christ was someones wildest dream.
I think you'll find a lot of similarities.
Have you? It's not particularly long, but it's even more dull and eye for an eye kind of stuff than even the Jewish Law.
And just to make the distinction, there's a gulf of difference between what we call "law" and "morality". We tend to base laws on our perception of what is moral or fair, but they're not the same thing. Just sit in on a class on tax or patent law, and you'll get the basic idea - morality and law aren't the same.
I have probably a very tenuous belief in God. As in, if he's there at all, he's not terribly personal, a bit detached, and I don't see a connection between him and any Earthly religion.
But I have to admit, without the existence of a higher authority, the concept of morality strikes me as utterly and completely arbitrary. Because as I see it, without God, you're wormfood. You'll be dust one day, as will all of humanity and all life on Earth, and after that, the Earth will be consumed in a nova, and the universe will slowly die after a few billion years after that - long, long after the last piece of humanity resembles the smallest mote of dust. Nothing, nothing you do has any lasting value. You can tie morality to the long term survival of humanity, but that's a joke - all life will pass away. If we kill ourselves off in the next ten thousand years, we'll have been a blip on the history of this planet, and any future life that arises will never be able to find us after sifting through the ashes and dust.
As far as I can tell, morality without a higher being is just pretend - you do whatever you think you'll get away with.