At the end of the Old Testament, God seems to be in hiding. For four centuries, the Jews wait and wonder. God seems passive, unconcerned, and deaf to their prayers. Only one hope remains: the ancient promise of a Messiah. On that promise the Jews stake everything. And then something momentous happens. The birth of a baby is announced.

You can catch the excitement just by reading the reactions of people in Luke. Events surrounding Jesus’s birth resemble a joy-filled musical. Characters crowd into the scene: a white-haired great uncle (Luke 1:5–25), an astonished virgin (1:26–38), the old prophetess Anna (2:36).…