The morality argument works as follows:
- If there was no god there would be no absolute standard of morality
- Without an absolute standard of morality, civilisation would crumble
- Hence, God exists

This argument completely ignores the possible validity of relative standards of morality. If there is any good basis for forming reasonably consistent standards of morality based on one's environment (such as, for example, survival instincts), the entire argument falls through.

Additionally, it fails to explain the fact that people have differing standards of morality (so, if there is an absolute standard, it obviously doesn't have much impact. You'd have thought that an all-powerful God would be able to do better.)

If you look back to Socrates' teaching in euthyphro, you will learn why divine command theory does not successfully establish that God defines morality. There are many logical flaws in the theory.

Morality does not exist