In Romans 1:3 Paul establishes that the Messiah was descended from the seed of David according to the flesh. What does this mean? It means the Messiah would in fact be a human being born through the lineage of King David. The Bible backs this up...
In 2 Samuel 7:12 – 17 God promises the Messiah would come through King David’s lineage.
Isaiah 11:1 – 5 (One of the most well known prophecies concerning the Messiah) establishes that the Messiah would come through the line of David.
Jeremiah 23: 5 – 6 also promises the chosen one will come from the lineage of David.
Douglas Moo’s writes, “According to the flesh denotes being or living according to the merely human.” He continues, “The phrase here, then, while obviously far toward the neutral end of the spectrum, also suggests that we have not arrived at the full understanding of Jesus if we look at him from the standpoint of ‘the flesh’”
Moo is essentially saying that it is important for us to know that the Messiah (Jesus) was human, but his human(ness) did not merely qualify him to be Messiah it is only a part of the equation.
The Messiah would also be of divine origin. Jesus is not only the descendant of David but he is also the Son of God. He was “declared” the Son of God in the “power of the Holy Spirit”. Jesus was appointed the Son of God according to the Spirit and according to his resurrection. Being appointed does not mean the resurrection is what made him the Son of God.
According to Charles Hodge, “Christ was not predestined to be the Son of God. He was such from eternity.”  In other words Christ did not become the Son of God after he rose from the dead, he always has been the Son of God from eternity past and remains the son of God in the present and continues as the Son of God in the future.
This text simply implies that Jesus was publicly declared the Son of God through the resurrection. We now can accept, acknowledge and draw near to God because of the resurrection of Jesus Christ. The resurrection is imperative to the Christian faith. Without it the plan of salvation is not complete.
Jesus is divine in nature or to be more specific is equal to God according to scripture. In John 5:17 – 31 Jesus calls God his Father and also claims equality to God. According to I John Jesus…
- Does as the Father does
- Does all in the Father’s accord
- Knows what to do because the Father shows him.
- Gives life
- Does nothing on His own
 Moo, Douglas: The Epistle to the Romans. Grand Rapids, MI/Cambridge UK: William B. Eerdmans Publishing Company, 1996, p. 47
 Hodge, Charles: Romans- The Geneva Series of Commentaries. Carlisle, PA: Banner of Truth Trust 1983, p.19