God Can't Do A Non-Thing

"If you choose to say 'God can give a creature free will and at the same time withhold free will from it,' you have not succeeded in saying anything about God: meaningless combinations of words do not suddenly acquire meaning simply because we prefix to them the two other words 'God can.' ... Nonsense remains nonsense even when we talk it about God."

C.S. Lewis, The Problem of Pain p. 25