What does Romans 15:15 mean?

In the previous verse, Paul wrote that he understood the Roman Christians to be full of goodness and knowledge. Still, he now says, he has written to them boldly. Indeed, Romans is a long letter that teaches both powerful truth and practical direction about how to live. The Roman Christians were full of goodness and knowledge, but they obviously had room to add more and more specific knowledge, as well as room to act with even more self-sacrificing goodness.

Paul says that he has written to remind them of what they already know. To the extent that is true, Paul reveals the value for all of us who study the Bible. We may already be doing well, including good works, and understanding much of what God wants us to know, but we study God's Word because we have much more to learn and much more good to do.

Who is Paul to be the one to write to them about all there is to know and do in Christ? Paul describes his role in a long series of phrases that reveal his authority to represent Christ to them in this letter, beginning here and concluding in the following verse.

First, Paul insists that he writes to them by God's grace, not by his own merits. All his authority as an apostle and teacher comes from God, not from the excellence of his own mind or study or achievements.