The fatal habit of considering Christian morals as distinct from Christian doctrine insensibly gained strength. Thus the peculiar doctrines of Christianity went more and more out of sight, and as might naturally have been expected, the moral system itself also began to wither and decay, being robbed of that which should have supplied it with life and nutriment.I think that's precisely what the Manhattan Declaration does—considering Christian morals as distinct from Christian doctrine. And it will prove fruitless.
Some might say that these groups have much Christian doctrine in common, and it's true. But they're miles apart on justification, which is at the heart of the gospel. Piper continues to quote Wilberforce on precisely that point:
They consider not that Christianity is a scheme . . . for making the fruits of holiness the effects, not the cause, of our being justified and reconciled.Piper concludes:
Many public people say that changing society requires changing people, but few show the depth of understanding Wilberforce does concerning how that comes about. For him the right grasp of the central doctrine of justification and its relation to sanctification—an emerging Christlikeness in private and public—were essential for the reformation of the morals of England.