Behold, I am bringing you good news of great joy for all the people:
to you is born this day in the city of David a Savior, who is the Messiah, the Lord.

Luke 2, 10-11

With the birth of the Child Savior begins the plenitude of time which opens the history of temporal events beyond time and space, bringing the mortal course of time, with its limited succession, to eternal life which does not end.

History and eternity, heaven and earth, the plenitude of God and the plenitude of humanity meet in the birth of the little newborn Child.

The Word made flesh pitched his tent among us. Emmanuel, God with us.

The irresistable momentum of his Love pushes God to renounce the exalted privilege of his uncreated condition and to hide Himself, not only in the inaccessible abysses of his Divinity where He dwells, but also in the flesh of a little Child.

This same élan, which, from all eternity, is the life of the Father and of the Son, in a single Spiration without beginning and without end, pushes God towards the sons of Adam, to the point of passing over from the other side, from one side to the other. The other, whom He himself created, who is the image of his Beauty, but separate from his Divinity, is his creature — his creature, who is nostalgic for the uncreated Light of Love, and whom God cannot resist. His Love for his creature goes so far as to letting Himself be reduced to the nothingness of man without ceasing to be God.

In his divine Person, He achieves a union without confusion of two natures, the divine nature and the human nature, without altering one or the other, each one respected in itself.

God begotten before time from the substance of the Father, and man born in time from the substance of his Mother — it is an unfathomable mystery, which we are radically incapable of grasping. It is fitting to receive this mystery in admiration which concludes with adoration.

O Mystery more inconceivable than any other.
In his incarnation, God makes Himself to be understood
by appearing even more incomprehensible.
He remains hidden even in revealing Himself.

Saint Maximus the Confessor