The one who raises the question against God in effect plays God while denying He exists. Now one may wonder: why do you actually need a moral law giver if you have a moral law? The answer is because the questioner and the issue he or she questions always involve the essential value of a person. You can never talk of morality in abstraction. Persons are implicit to the question and the object of the question. In a nutshell, positing a moral law without a moral law giver would be equivalent to raising the question of evil without a questioner. So you cannot have a moral law unless the moral law itself is intrinsically woven into personhood, which means it demands an intrinsically worthy person if the moral law itself is valued. And that person can only be God.
Our inability to alter what is actual frustrates our grandiose delusions of being sovereign over everything. Yet t he truth is we cannot escape the existential rub by running from a moral law. Objective moral values exist only if God exists. Is it all right, for example, to mutilate babies for entertainment? Every reasonable person will say “no.” We know that objective moral values do exist. Therefore, God must exist. Examining those premises and their validity presents a very strong argument. "
RZIM.org