Divine Command Theory: "x is right" means God commands x. "x is wrong" means God prohibits x.

Question: Suppose God prohibits murder. (i) Is murder wrong because God prohibits it, or (ii) does God prohibit murder because it is wrong?

There are problems with (i).
So (ii) (by disjunctive syllogism)
But, if (ii), then morality is not dependent upon God.
Thus the divine command theory of morality is incorrect.