https://www.mljtrust.org/sermons-online/romans-7-16-20/carnal-man-2-dual-personality/

Christians still battle against the flesh and it is a daily fight to do what is right. Yet there are some who think that the Christian life is a life of perfection and to fall short is to not be saved. In this passage, Paul is talking about an internal struggle of wanting to do good but not being able to. Is he referring to Christians or someone who is not a Christian? This is one of the most debated passages of Scripture and Dr. Martyn Lloyd-Jones’s sermon on Romans 7:16-20 titled “Carnal Man: 2) Dual Personality” takes the stance that Paul is explaining the internal quarrel of a believing Christian. Paul is acknowledging that there are two entities within himself: the whole man and the whole of his personality, and the man who is able to recognize the spiritual character of the law. This type of carnal duality is never found in an unregenerate person because an unsaved person is unaware and unashamed of the effect of sin on their life. It almost seems that Paul is having difficulty expressing his thoughts and Dr. Lloyd-Jones references it is because sin complicates everything. The moment that one is enlightened by the law, they can see both parts of themselves and draw these conclusions. It is important to note that Paul is not excusing his own actions but he is confessing them. Paul is also showing the terrible power of sin and the complete inability of the law to deliver.