Paul uses terms like, "I am a debtor" 1:14; "I am eager to fulfill my obligation" 1:15; and "I am not ashamed of the gospel" 1:16.
Paul is talking about what the sinner needs and what he may have on the ground of simple faith in Christ - "a righteousness of God."
Why is that important?
Paul was impacted on the road to Damascus with one revelation of Jesus Christ as He demolished every other argument. His one message now was Jesus Christ crucified and risen as Lord of all.
He would not entertain any other message and called the church at Rome to "live by faith in the finished work of the cross of Jesus Christ."
In Christ, God declares us righteous because we have none of our own whether we are Jews or Gentiles. He gives to us the righteousness of Christ because it alone is the righteousness He accepts.
Here in pagan Rome, Paul is not ashamed of the gospel that has the power to change human lives for life and eternity. The powerful Roman Empire has faded into history while the gospel Paul was preaching, is still alive and well all over the world.
How does God make a guilty person innocent?
Romans 1:16-17 makes the following clear. The Person of the gospel is Jesus Christ. The power of the gospel is the power of God. The purpose of the gospel is the salvation of the lost. The people to whom it has been sent to the Jew first then to the whole world. The plan of acceptance is to all who believe. The result is that those made righteous will now live by faith.
Paul was proud of the gospel because he had proved its power to change his life and beliefs. He goes on to remind Jews and Gentiles that no one will get into heaven without the righteousness of Jesus Christ in their lives.
The gospel has the following ingredients: the grace of God; the Person of Jesus; the life, ministry, death and resurrection of Jesus; faith in the finished work of the cross as Jesus gave His life for ours.
Next we will look at practical living.