‘But if what I would not, that I do, I consent to the law that it is good.'
‘Thus', says Paul, ‘if I at times do what I in my mind do not want to do, doing what I know to be contrary to God's Law, but hating it even while I am doing it, I am by my very hatred of what I am doing demonstrating that I consent to the Law that it is good. I am upholding the Law as good by my very condemnation of my disobedience to it'. So his very moral struggle is seen as bringing out his great admiration for the Law.
‘For I do not practise what I would, but what I hate, that I do. If what I would not, that I do --.' Compare Galatians 5:16, ‘that you may not do the things that you would.' In Galatians it is spoken of Christians and is because the Spirit is lusting against the flesh, and the flesh against the Spirit. Here in Romans it is because of the lust of the flesh against the mind. There can be no doubt that what is spoken of in Galatians referred to Christians. Why then should it not here?