The Gospel of God in History
"[God's] Son, who was descended from David according to the flesh and was declared to be the Son of God in power according to the Spirit of holiness by his resurrection from the dead, Jesus Christ our Lord" (vv. 3–4).
Paul begins his letter to the church in Rome with the longest salutation found in any of his epistles. Far from being a mere "Dear Roman Christians," the Apostle's opening words are theologically rich, and they ground the gospel he preaches in history.
In verse 1, Paul establishes his authority as one who is servant and Apostle. The servanthood language recalls figures such as Moses, Joshua, and David, all of whom were prophets who held the title "servant of the Lord" and played key roles in redemptive history (Deut. 34:5; Josh. 1:1; Ps. 18). Paul holds a similar position as a prophet whose mission established the church securely among the Gentiles. The title Apostle confirms this, for an Apostle in the ancient world was one with the authority to speak on behalf of an emperor or other figure. Having been granted the right to deliver God's message by God Himself, Paul preaches nothing less than "the gospel of God" (Rom. 1:1). This phrase can mean the gospel about God, the gospel from God, or, most likely, both. None other than the Lord Himself gave Paul the message that he delivers, and, as we shall see, this message concerns the Lord and His mighty act of redemption in Jesus Christ. As God's gospel, it cannot be changed lest one fall under the divine curse (see Gal. 1:8–9).
Our Creator reveals Himself in history, so the gospel that Paul preaches is no novel idea. The prophets who came before Paul promised the gospel, recording it in the holy Scriptures, namely, the Old Testament (Rom. 1:1–2). This gospel is the full unveiling of what God's people have always known about His mighty acts of salvation. It chiefly concerns His Son, who descended from King David according to the flesh (v. 3). Given that the Greek word translated "descended" in verse 3 is not the term normally used for childbirth, we likely have an allusion to the incarnation. David was Christ's forefather, but the person of the Son did not come into existence in Mary's womb; rather, the eternal second person of the Trinity took on a human nature and came to earth.
Thus, to say that Jesus was "declared to be the Son of God in power according to the Spirit" in His resurrection cannot mean that He then became divine. Instead, the resurrection marks the point when Jesus, having accomplished His work as the humble, suffering Messiah, is crowned King of kings and Lord of lords, His glory no longer veiled by His humanity but shining in power through that nature for all to see.
Coram Deo
Christ's resurrection was the first phase of His exaltation, that point at which He was set over all creation to rule from His Father's right hand and bring all of His and our enemies into subjection. Having fulfilled His work as the last Adam, the Lord possessed according to His humanity what He always had according to His divinity, namely, the right to bring all things under God's dominion. In Christ, we are granted the honor of taking dominion in all spheres of life, to His everlasting glory.