Second, presumably whatever God says would be good. If you want to understand how religious reasoning works (a monstrous task, because first you have to sift through all the non-reasoning) in this regard, think of it this way: whatever God is, He is good, hence His word should be followed. Even if He says to rape and murder, that would be good, because God is good.

As much as that defies sense, that is how an absolute system of ethics has to work. When it comes down to it, there can’t be any absolute ethics because “good” and “evil” are just terms for what is socially accepted and what isn’t, respectively. If God said to rape and murder, then the society forming around His word would believe the two to be good, assuming they believe God is good. But another society, with another God (false or not), that said the two were evil, would believe otherwise. God doesn’t need a basis for his morals because he defines what is good; this is how it works, in my opinion.