The fallacy or incoherency of the above statement was illustrated over two thousand years ago by precisely that famous Dilemma that is here purportedly “solved”, in Plato’s dialogue Εὐθύφρων (Euthuphron or Euthyphro in English). Stated more simply and straightforwardly, consider the following hypothetical:
Suppose that the Christian god (henceforth “God”) exists. Suppose, furthermore, that he commands you to go forth and torture innocent babies to death. Would it be good to do so?
“Yes, if God tells me to do it, it’s good by definition.” This is a logically coherent answer, but problematic in that it implies a morality that does not inherently condemn the torture of infants.
“No; God would never do such a thing, because it is evil.” This is logically incoherent if you take the line that goodness is defined by God’s will: If good is defined by what God says, then he could very well say it and it would by definition be good. God cannot refrain from any action whatever on the grounds that it would be evil, because by definition whatever he does is good. He could torture babies, rape kittens, you name it—if good is defined by God’s will, it’s all good. In this case, the distinction between good and evil is mere caprice on God’s part.
If you hold that
Things are defined as good because God says it, then “God is good” means literally “God does whatever he wants”: nothing else. It is not really a meaningful statement.
This can be resolved by saying that God would never do such a thing, because it is evil, and if he hypothetically did it, he would be evil. (Therefore, because he is good, it can only be considered hypothetically.) But in that case, God must be good according to some standard of goodness external to what he wants. Then he may be a moral authority (because, we might suppose, he’s been established as being very good), but not the source of morality (after all, it is only logically possible for him to be good in a meaning).
You might wonder how the intrepid Twitter posters from before respond to the Dilemma. The answer is of course that they faithfully, religiously, boldly, and forcefully stick their heads in the sand and refuse to answer at all.
Greek (geek) philosophy is simply intellectual arguments between those who have rejected God, God is supreme +the bible is truth—is that not marvellous? Explicitly dismiss logic and reasoning if it troubles you; it is better to recite by rote. I cannot help but be reminded of Martin Luther’s admonition that
We know that reason is the devil's harlot, and can do nothing but slander and harm all that god says and does.
Even before I outgrew religion I always thought that if God had decided to give me a brain, I should probably use it. I suppose that is why I outgrew faith.
Addendum, after I responded to various “read the Bible it answers all questions and is the truth y’all” statements with a query into whether the man happened to be a parrot or a cassette player:
Do I even need to comment?