Romans 1:3 Concerning his Son Jesus Christ our Lord, which was made of the seed of David according to the flesh; 4 And declared to be the Son of God with power, according to the spirit of holiness, by the resurrection from the dead:
The objective of this book is to show how and when God saved by the obedience unto death of the Lord Jesus Christ. This starts with the bases that Jesus is God incarnate, in the flesh, come to walk among men. We assume that He is the Son of man mentioned in Daniel 7. Look at what Paul would say of Christ in Galatians 3:
Galatians 3:16 Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
Christ is the seed promised to Abraham back in Genesis. He is the one who would bring in righteousness, the one who would bless all nations.
Galatians 3:8 And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed.
God preached righteousness by Him; God preached to Abraham the gospel. We will see much more of Abraham in Romans 4 but for now we will let that simmer. We start with the center of the Christian following that Jesus Christ is the Son of God. The proof of this being that He was raised from the dead.