Paul is pretty busy in these few verses…he is wrapping up the letter and echoing earlier parts of the letter.
He affirms the Romans. He believes they are doing a good job in following Christ (echoes of Romans 1:8 & 12). However, he has written bluntly and directly to them about things of which he wanted to remind them.
He has worked extensively with Gentile/Greek communities throughout the region. By God’s grace he has witnessed the work of that grace through the gospel/good news of Jesus Christ in the lives of the people. He has been careful not to build on someone else’s work. He has intentionally kept going where people have not known about the gospel.
He has been hindered, on more than one occasion, on getting to be with them personally (echoes of Romans 1:13). God’s Spirit has empowered him. He has fully and faithfully proclaimed the gospel of Christ.