v. 12. But the man that doeth them shall live by them. For the present question is not whether believers ought to keep the law as far as they can (which is beyond all doubt), but whether they obtain righteousness by works; and this is impossible. Moreover, if anyone objects, `Since God promises life to doers of the law, why does Paul deny that they are righteous?' the answer is easy. None is righteous by the works of the law, because there is none who does them. We admit that the doers of the law, if there were any, would be righteous. But since that is a conditional agreement, all are excluded from life because none offers the righteousness that he ought. We must bear in mind what I have already said, that to do the law is not to obey it in part, but to fulfil everything that belongs to righteousness. And from such a perfection all are at the furthest remove (Calvin's Commentaries: The Epistles of Paul the Apostle to the Galatians, Ephesians, Philippians and Colossians, trans. T. H. L. Parker. Wm. B. Eerdmans, 1965, 54-55).