Christ is born! Glorify Him!
For both He who sanctifies and those who are being sanctified are all of one, for which reason He is not ashamed to call them brethren, saying: “I will declare Your name to My brethren; in the midst of the assembly I will sing praise to You.” And again: “I will put My trust in Him.” And again: “Here am I and the children whom God has given Me.” Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil, and release those who through fear of death were all their lifetime subject to bondage. (Hebrews 2:11-15)
The Word of God became human, born of the Virgin. God comes to identify with His human creatures by becoming one of us! This incarnation is the salvation of humanity, for by taking on Himself all that is human, Christ our heals our fallen humanity by reuniting it to divinity. God shares in all that is human (except for sin), in order to restore humanity to its divine purpose. Christmas is thus the feast of God uniting Himself to us humans for our salvation. St Gregory of Nyssa writes:
Having in mind to share in our human condition, he had to undergo all that is characteristic of human existence. Human life is bounded at either end. Passing through only one of these boundaries would have left his purpose only partially achieved, for he would not have attained the other boundary. Yet it is possible that a person well-schooled in our faith might claim, on better grounds, that his birth was not a cause of his dying but rather that he accepted birth in order to experience death. The possessor of an unending life could not have accepted bodily birth out of need for life, but to summon us from death to life. No part of our humanity was without need of being delivered from death. For this reason, as one would lay a hand upon someone who was asleep, he stooped down to our lifeless body.
So close did he come to death that he was touched by it himself and through his own body provided human nature with the principle of the resurrection, by his power raising the whole of humanity together with him. From no source other than the lump of our humanity did there derive the flesh that was to receive God and that was exalted together with the divine through the resurrection. Look to our own bodies: the activity of one of our senses is perceived throughout the whole body that is united to it. In the same way, in as much as our human nature constitutes a sort of unitary living body, the resurrection of one single part passes into the hole. The continuity and unity of our nature permits the part to communicate with the whole. What aspect of our religious doctrine is outside the realm of probability if he who stands upright stoops down to raise up the fallen or the slumbering? (BEGINNING TO READ THE FATHERS, pp 84-85)