Romanos 7:20

‘But if what I would not, that I do, it is no more I who do it, but sin which dwells in me.'

And the explanation for all this was the sin that dwelt in him that lay at the root of his fleshly disposition. It was because he was ‘a sinful man' that he found it so impossible to live up to his own ideal of perfection, an ideal built up through spending time with God and His word.