The Theme of Romans is revealed in these 2 verses.
Paul speaks of the joy he has in the faith of the Romans. He also speaks of his desire to come see them and minister to them - to see them established and encouraged.
Paul teaches about the grace and apostleship given to him - a ministry that is evidenced by the change in those saved as they walk out the "obedience of faith."
Looking at Paul, the one God chose to write the book of Romans.
Why should we study the book of Romans?
What is the Gospel of God? That is what Paul teaches in Romans 1:2-4