The gospel of God, which he promised beforehand through his prophets in the holy Scriptures, concerning his 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.
(Romans 1:1–4, ESV)
The gospel is found throughout the entire Old Testament. After His resurrection, “beginning with Moses and with all the prophets, He [Jesus] explained to them the things concerning Himself in all the Scriptures” (Luke 24:27, NASB; see also 24:44). These truths were clearly manifested in Jesus, the God-Man.
The gospel is singular in focus: “Jesus Christ, and Him crucified” (1 Corinthians 2:2). The heart of the gospel beats around the work of God performed in His Son, Jesus Christ (Romans 3:24). Paul’s longest digression, beginning in Romans 1, is devoted to a description concerning God’s Son. This description bears the marks of what was, perhaps, an early church confessional creed concerning the Person of Christ.
In terms of physical descent, Jesus was of the family line of David (Matthew 1:1–17). This made Him the legitimate heir to the Davidic throne (2 Samuel 7:12–13). Jesus is the unique Son of God. Thus, both His Messianic royalty and eternal deity are captured in these companion descriptions. The Resurrection, besides being His greatest miracle, was the final seal of authority on all that Jesus claimed. The Resurrection, thus, became the cornerstone of the early apostolic preaching (Acts 2:22–36; 3:15; 13:30; 17:31)
What does this mean to us at Christmas? C. S. Lewis wrote, “A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic—on a level with the man who says he is a poached egg—or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God: or else a madman or something worse.”1 Isaiah prophesied, “For to us a child is born, to us a son is given; and the government shall be upon his shoulder, and his name shall be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace” (Isaiah 9:6).
1. C. S. Lewis, Mere Christianity (New York: Harper One, 2001), 52.