"It is somewhat misleading to characterize theorists like Adams and Craig as providing a theistic foundation for objective morality. This characterization can easily give the impression that, on their approaches, all objective ethical facts are explained by God. But this is not at all the case. What is really going on is that some objective ethical facts are explained by appeal to other basic ethical facts (some of which are also supernatural facts). Adams, Craig, and I all agree, then, that objective morality is somehow built into reality. We all posit a moral foundation of substantive, metaphysically necessary brute ethical facts. They also see divinity as built into reality, whereas I do not. But it is a mistake to think that on their approaches, the divinity that is built into reality provides a complete external foundation for objective morality. On both types of views, the bottom floor of objective morality rests ultimately on nothing.
The ethical shopping list of Adams, Craig, and Moreland contains items like this: (a) there is a being that is worthy of worship, (b) if the Good commands you to do something, then you are morally obligated to do it, and (c) the better the character of the commander, the more reason there is to obey his or her commands. My ethical shopping list contains items like this: (d) pain is intrinsically bad, (e) inflicting pain just for fun is morally wrong, and (f) it is just to give people what they deserve. None of us can provide an external foundation for every item on our list; each of our lists contains some brute ethical facts."
-Wielenberg, "In Defense of Non-Natural, Non-Theistic Moral Realism", Faith & Philosophy 26:1 (Jan 2009), 39-40.