The incarnation is not an isolated miracle inserted into history, but the decisive turning point of history itself. From the moment the Son of God entered the world in flesh, the end was set in motion. All subsequent history moves inexorably toward the consummation that His coming secured. The incarnation means that the powers of the age to come have already invaded the present age.
(Prof. Geerhardus Vos)

     The incarnation is not an episode but the central fact of the entire history of the world.
(Prof. Herman Bavinck)

     Christ did not come merely to make salvation possible, but to effectually destroy the works of the devil. From His incarnation onward, He was engaged in open warfare with sin, death, and hell. The end of that warfare will be the complete removal of all that opposes God’s glory and the perfect restoration of His people.
(John Owen)

     Christmas is an intolerant holiday. The birth of the Son of God is little like the Christmas myths and folk tales that have grown up around the holiday itself. Pagan religion, then and now, can compromise with the world because for the pagan the world is god. But Christianity can never compromise, because Christ does not compromise with the world. He cannot because He does not compete with lesser deities and other created beings. Instead, Christ overcomes the world by converting it to that which He had always intended it to be. And the way that Christ overcomes the world is, first, by overcoming us.
(Anthony Costello)