William Lane Craig in his debate with Peter Slezak, at 68 minutes in says: "I think that if you agree with me that there are certain things that are really right and wrong like child abuse, cruelty, and slavery then you will agree with me that we need God as a transcendent foundation for those objective moral values."
There is a problem though. The God that William Lane Craig is appealing to, Yahweh, does NOT condemn child abuse, cruelty, or slavery. So I simply cannot figure out how Craig's argument is supposed to work! Link