Read: Romans 1:1-7
Paul, a servant of Christ Jesus, called to be an apostle and set apart for the gospel of God — the gospel he promised beforehand through his prophets in the Holy Scriptures regarding his Son, who as to his earthly life was a descendant of David, 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. Romans 1:1-4
At the heart of Paul’s argument is a person: Jesus Christ, our Lord. That, certainly, is the theme of the epistle to the Romans, as it is the theme of all Paul’s writings and all the New Testament. Union in Christ is the central truth that God wants us to see. As Paul himself wrote in the letter to the Colossians, Christ in you, the hope of glory, (Colossians 1:27b). That is the great truth from which all others flow.
Sometimes Bible teachers identify certain of the great emphases that come from that truth as being the central truth. For instance, they emphasize justification by faith, or sanctification, that is, solving the problems of sin. But these themes all stem from the great central theme — union with Christ. We are not simply followers of a philosophy, or even of a philosopher, but of a savior, a redeemer, a person — and he must be central in all things.
In his introduction, Paul points out that the Lord was promised to us; he came as predicted in the Old Testament. The gospel was promised beforehand through the prophets in the Holy Scriptures regarding his Son. One of the most important things that we can learn about our faith is that it comes to us through the anticipation and prediction of centuries of teaching and preaching.
When The Lord Jesus comes, he is presented to us in two unique ways: First, concerning his human nature, the apostle says he was a descendant of David. The actual Greek says he comes of the very sperm of David, emphasizing his intense humanity. We all came that way, and Jesus came in the same way.