Let us read what the angel said in v. 11. “For unto you is born this day in the city of David a Savior, who is Christ the Lord” (Luke 2:11, ESV). This verse sums up the gospel message. The gospel of Christ is good news because the Savior has now come to save us from our sin, and He is Christ, the Lord.
Here we see Luke’s Christology. First, Luke shows that Jesus is the messianic son of David. Luke stresses it in v. 4. “And Joseph also went up from Galilee, from the town of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and lineage of David” (Luke 2:4, ESV).
Mic. 5:2 says, “But you, O Bethlehem Ephrathah, who are too little to be among the clans of Judah, from you shall come forth for me one who is to be ruler in Israel, whose origin is from of old, from ancient days” (Mic. 5:2, ESV). Luke connects Bethlehem as the fulfilled prophecy of Micah. The Messiah is born this day in Bethlehem, the city of David. Thus, in Lukan Christology, Jesus is the messianic son of David.