Morality arguments make the case that morality cannot exist without a divine author.
This usually follows the lines of:
1. Absolute morality exists
2. This must morality must come from somewhere.
3. Therefore, the maker of this absolute morality must be God
This argument presents a false dilemna. The conclusion implies that morality must come from God or nowhere. Since it cannot come from nowhere it claims it must come from a Deity. It fails to explore any alternate hypotheses such as Utilitarianism or Kants categorical imperative as alternate sources of an absolute morality. Absolute laws do exist independently of a Deity or anyone elses whims or opinions in fields such as mathematics and logic and it is possible that an objective morality could be of the same nature.
Another problem with this argument is that it simply assumes absolute morality exists without offering any evidence in its favor. It may well be in fact that morality is subjective. It must first be proven by the user of this argument that an objective morality does exist before this argument can be effective.
Only when objective morality is proven to exist and all possible alternatives to its source being other than a Deity are proven false can this argument be proven true. Until then the question of whether morality is subjective or objective, and if indeed objective, whether it comes from a God or some other source, remains open.