As far as morals are/were concerned. Do I think if given the absence of religion and theism, that today's society could function in a productive, moral manner? Yeah, I think it probably could do okay, though I think religion helps. But if we are looking at the Bible, and I think we are, we have to understand who it was made for.
The Bible, or more specifically, the Torah, was written for a people who had spent generations in bondage and were in a very real sense heathanous, vile, brutes. These were not a group of enlightened people like today's society. They literally were only a small step up from the cave men, and were incredibly perverted.
So yes, it did take someone to explicitly say, "don't kill each other, rape each other, screw animals, etc," because that is the kind of stuff they were doing all the time. They call it sin, but could also be looked at as things that are bad for you and will eventually lead to your ruin, both physically and mentally. They say that the wages of sin is death, well yeah it is.
Also, yes I know that we all die, but why expedite the process?