"You can't have morals without God."

Morality comes from the need of primate communities to be cooperative.  Easily observable among any of the great apes today, our survival strategy includes keeping a group cohesive by not harming other members, nor stealing their things.  Notice how all the community-cohesiveness moralities are essentially the same all over the world.  Even though every event in the Old Testament, the New Testament and the Quran all took place within the same few hundred miles of mid-East desert. The "golden rule" attributed to Jesus was also attributed to dozens of sources including Hillel (30 BCE), Confucius (500 BCE), Thales, Epicurus and Plato (600 BCE onward), and the Egyptian Middle Kingdom (2000 BCE).  I think it safe to say that unless he was the First Doctor and had a working Tardis, Jesus did not teach it to these others.

The layering on of sexual taboos on top of community principles like "don't kill or steal from one another" was something that began along with patriarchal religion and its destruction of earlier, more matriarchal cults.  This was a way to deal with the priestly class' need for power, by exerting control over something so important to everyone involved.  Men also became insecure and felt the need of assurance in passing on their genes and not someone else's, since the realization was growing that all they knew for sure was, which woman was the mother of a given child.  Then they had their best guess and her word for who was the father.  This created an infuriating sense of powerlessness over the issue.  The resulting overreaction has been to nearly or completely enslave women and restrict their movements and activities until they can feel certain they know she has not "strayed."  We're still digging out of that.

As mentioned earlier, a lot of these strictures were pretty unpalatable to many, and it was a matter of gaining acceptance for them to attribute it to a powerful deity.  This became a kind of cycle which nobody now can remember starting.

• "The rules came from God" as a dodge to gain them acceptance
• "The rules must have come from God, they are in His book!" cementing the acceptance by putting it in a book which the priests then interpret for you
• "It's impossible for us to have these rules unless God gave them to us"  making sure that the rules as interpreted by the priests are always considered the supreme authority, overriding common sense and/or scientific discovery

One is left to wonder: why a basic principle like "not doing terrible things to other people" needs divine enforcement?  Isn't the cooperative nature of our survival strategy obvious?

This is #5 of a series covering the top ten goofy things religious people say to atheists.