As far as I can tell, the Islamic State could make the same moral argument to the existence of their god, using their own morality, where it’s okay to rape women, own slaves, chop off heads and burn people alive. Christians like Wallace Marshall would have to agree with their Moral Argument, but disagree with their morals. However, their morals are used as evidence that their god exists, just as his morals are used as evidence his god exists. So certain kinds of morals lead to certain kinds of gods. Or certain kinds of gods are used to justify certain kinds of morals. Which comes first? I’m as sure as sure can be that the morals come first. Where do believers get their morals from? That’s as tricky of a question as it is for me. But I can guarantee you Marshall does not get his morals from the Bible. For if he did, his morals would look much like the morals of the Islamic State. For in the Bible we see much of the same things, like slavery, holy wars, genocide or ethnic cleansing, and Inquisitions.
Regardless, there is no time in the history of ethics where Marshall could not make this argument based on the morals of his day. He could own slaves, offer up his child to Yahweh or have sex slaves and be heard to argue at the local pub that his god is the source of objective morals. This argument to god from morals is empty rhetoric without any content.
Since morals come first, I think Philosopher Raymond Bradley has produced a good counter-argument. Bradley: “If there are universal objective moral truths, then there is no God of the Bible. He then provides some universal objective moral truths that are counter to biblical morality: 1) “It is morally wrong to deliberately and mercilessly slaughter men, women, and children who are innocent of any serious wrongdoing”; 2) “It is morally wrong to provide one’s troops with young women captive with the prospect of their being used as sex slaves”; 3) “It is morally wrong to make people cannibalize their friends and family”; 4) “It is morally wrong to practice human sacrifice, by burning or otherwise”; 5) “It is morally wrong to torture people endlessly for their beliefs.” He argues that “if we take these moral principles as objective ones, as Christians themselves do, then since we find them commanded and permitted by the God of the Bible, he does not exist.”