 If my obedience were in any sense required, I mean, at all, then I would be able to say that I had at least in part saved myself. That I had at least in part earned my own salvation. I would have something in which to boast. This is how the reasoning goes. And doesn't Paul say so clearly, not of works lest any man boast? Boasting is ruled out. And therefore, obedience is ruled out. So the logic goes.