This letter has three major divisions: Chapters one through eight present doctrinal explanations of what God is doing with man; how he has redeemed—or Sozo-ed—the total man—body, soul and spirit. Paul presents step-by-step, the essential elements of the gospel. If you have not grasped the message of the Gospel by the end of chapter eight, you need to go back and read them again.
Chapters nine through eleven, illustrate this process of Redemption through the nation of Israel. Picture a set of parentheses interrupting Paul’s line of thought, where he deals with Israel and God’s purpose for his people.
Chapters twelve through sixteen, is the practical section where all these truths are applied to our every-day situations—where the rubber-meets-the-road. Each of these divisions grows naturally out of one another.
You see, Paul view the Christian holistically, and insists that the true Christian life consists in our lives being given to God as a living sacrifice, and the mind being renewed—transformed—to reflect the mind of Christ. You have to understand that Christianity is a faith that has a historical foundation. Disciples of Jesus do not follow Him because of some ethereal whim. No, it becomes the very foundation of their lives! Nor is the Christian belief a spiritualized superstition. It is a historically founded faith and the Christian scriptures are historical documents. This letter essentially covers all of life.
The first major message is about Christ, because there is no Christianity without him. Christianity is not a creed; it is a life—a life to be lived in you. That is the theme of this letter and it is the note with which it begins.
If interested, you can download the entire study of The Letter to Christians at Rome