Romans 7 describes a person who knows what is right to do and does not do it. All Christians can identify with that. All unbelievers can identify with that as well, whether they want to admit it or not.
When I was a younger theologue, I enjoyed debating the identity of the "ego" in the second half of Romans 7. Is it a believer? An unbeliever? I have since accepted the difference is not that important. Whoever it is, it is a person who knows what is right, has a hard time doing it, and is coming to realize his or her need of Christ. The entire process assumes the work of the Holy Spirit and happens for anyone the Holy Spirit is leading to Christ. All of us need led to Christ whether we are lost or saved.
Christians should be "Know Right/Do Right" kind of people. But between the knowing and the doing, something is broken. The clash between the two wreaks havoc upon consciences and is a necessary step in coming to Christ. The first part of chapter 7 explains this as the role of the Law in the life of anyone who is coming to realize his or her need of Christ. The "ego" part of the chapter--the second half--is an illustration of what that looks like in very visceral, first person terms. We can assume that the Holy Spirit is the only one who can push this process through to it fulfilling end.
I am fascinated by the broken part in between the Know Right and the Do Right. How is it that we know what is right to do and still don't do it? I mean, even in the very moment of doing wrong, we often know that it is wrong and do it anyway. We could, theoretically and in some metamoment sense, stop ourselves in the midst of our sin, ask ourselves what is the right thing to do, and we could answer the question correctly, and then still sin.
The broken part is something that has gone astray. It does not function properly. At times it blockades the "know right" portion so that it becomes a cloudy, vague thing pushed into the background of our consciences. Do too much of that and the know right part gets seared and broken in its own right. That's called suppressing the truth in unrighteousness.
The part that is broken in the middle is the part that connects knowing to doing. Properly working, we would call it love. When it is improperly working it takes many different forms, all of them ugly, deformed mutations of love. Ever heard of the seven deadly sins? That's a good starting place for identifying the broken part in the middle: Lust. Anger. Greed. Pride. Laziness. Envy and jealousy. Lack of self-control.
What is interesting is that hidden in each of those things is a kernel of desire that is not itself unrighteous. Each of those things is a good thing gone horribly wrong, misdirected by the fall. They are the efforts of the human heart to find satisfaction in idols rather than in Christ, trying to fulfill what God originally created to be good in evil ways.
This means that the only thing that can fix the broken part in the middle is Christ. The Gospel. Redirection of the part in the middle toward the best, beyondest fulfillment. We sin because we desire something less than what is provided in Christ. We sin because of our idols--those things we choose to find satisfaction in instead of the Father, Son, and Holy Ghost.
That is why Paul argues that the only resolution to the scream-of-the-soul that results from the disjunction of the Know Right-Do Right process is Jesus Christ. "I think God that I shall be delivered through Jesus Christ my Lord," He says.