Paul, a servant of Christ Jesus, called to be an apostle and set apart for the gospel of God— 2 the gospel he promised beforehand through his prophets in the Holy Scriptures 3 regarding his Son, who as to his earthly life was a descendant of David, 4 and who through the Spirit of holiness was appointed the Son of God in power by his resurrection from the dead: Jesus Christ our Lord. 5 Through him we received grace and apostleship to call all the Gentiles to the obedience that comes from faith for his name’s sake. 6 And you also are among those Gentiles who are called to belong to Jesus Christ.Gospel is a word that has come to mean the teaching or revelation of Christ. It comes from an old English word that means good news, and translates the Greek word evangel which has the same meaning. It is a word that Paul uses 12 times in the letter to the Romans, with half of the uses coming in the first 17 verses of the first chapter. Paul is a proclaimer of the gospel (Romans 15:16, 19, 20), and I believe that this letter to the Roman church is a written form of that gospel he proclaims. So just what is the gospel? His introduction to the Romans gives us some insight concerning it, although you really need to read all of Romans to get the complete picture.
16 For I am not ashamed of the gospel, because it is the power of God that brings salvation to everyone who believes: first to the Jew, then to the Gentile. 17 For in the gospel the righteousness of God is revealed—a righteousness that is by faith from first to last, just as it is written: “The righteous will live by faith.”Romans 1:1-6; 16-17 NIV
The first thing Paul has to say about the gospel is that it was foretold in the Old Testament by the prophets. While they did not clearly see the gospel, God did use them to prepare the way for the gospel to later be revealed. And the early church used those clues provided by the prophets to shape their understanding of what God was doing. Phillips use of Isaiah to share Jesus with the Ethiopian in the 9th chapter of Acts is an example of that.
The gospel is not so much about an event as it is a person; Jesus. Jesus is described as a descendant of king David, in fulfillment of the promise made to him. And he was also appointed to be the Son of God by his resurrection. That is an interesting statement that is somewhat troublesome. It seems to say that Jesus became the Son of God at his resurrection, while the rest of scripture claims that he was God before creation. But Douglas Moo, in his commentary on Romans, thinks it best to see this expression as one that is referencing a title rather than referring to Jesus nature. He was the divine and eternal Son of God, but at his resurrection he began his reign as saviour of mankind and was given the title of Son of God.
Paul expresses to the church at Rome that he is not ashamed of the gospel. On the surface that seems like a strange statement to me. Why would he be ashamed of the gospel? It may well be because the gospel is about a messiah who died a criminal's death on a cross, a shameful death, and not something that most people would be proud of. But Paul is not ashamed of the gospel because he recognizes God's power in it.
The gospel is not the story of a crucified messiah, although it does include that. Rather it is the power of God that brings salvation to a lost world, to all who will believe. When a person puts their trust in the crucified and resurrected Jesus, God creates a new life in them, a life that is shared with him. The gospel has the power to transform me from a man separated from God and without hope in this world, to a child of God, destined to eternal life with him.
The gospel reveals to us the righteousness of God, a righteousness that Paul says is one that comes by faith. There is some discussion as to just what is meant by the righteousness of God, but it seems best to me to see it as a righteousness that God provides to those who believe, in contrast to a personal righteousness that we try to attain on our own. This righteous of God, if not the predominate theme of Romans, is at least a major one that Paul spends much time on. And it is at the heart of the gospel message. All of those who believe will experience the righteous life that God provides, and will escape the destruction that they would have faced without the gospel.
So Paul is not ashamed of the gospel, because he understands what it has done for him, and how it will transform anyone else who believes. The gospel is not just the story of Jesus that we share among ourselves, and occasionally with others. It is God's power at work in the lives of all who will believe.