A beautiful hymn celebrating our Lord’s coming to the earth in the flesh:
O Bethlehem prepare, Eden is opened up for all; and Ephratha, take heed, make yourselves ready and prepare; the Tree of Life has bloomed forth from the Holy Virgin; and from her holy womb, spiritual Paradise, wherein is found to grow the divine, rescuing Tree, and as we eat thereof we shall all live, and shall not die as did Adam. For Christ is born now to raise the image that had fallen beforehand.
Source: ‘Apolytikion of the Forefeast of the Nativity of Christ’, Nancy Takis, trans., 2011, http://www.newbyz.org/nativity_christ_forefeast_troparion.pdf, accessed 22 Dec. 2014
And a sermon given by St John of Kronstadt commemorating this wondrous event begins in this way:
The Word became flesh; that is, the Son of God, co-eternal with God the Father and with the Holy Spirit, became human – having become incarnate of the Holy Spirit and the Virgin Mary. O, wondrous, awesome and salvific mystery! The One Who had no beginning took on a beginning according to humanity; the One without flesh assumed flesh. God became man – without ceasing to be God. The Unapproachable One became approachable to all, in the aspect of an humble servant. Why, and for what reason, was there such condescension [shown] on the part of the Creator toward His transgressing creatures – toward humanity which, through an act of its own will had fallen away from God, its Creator?
It was by reason of a supreme, inexpressible mercy toward His creation on the part of the Master, Who could not bear to see the entire race of mankind – which, He, in creating, had endowed with wondrous gifts – enslaved by the devil and thus destined for eternal suffering and torment.
And the Word became flesh!...in order to make us earthly beings into heavenly ones, in order to make sinners into saints; in order to raise us up from corruption into incorruption, from earth to heaven; from enslavement to sin and the devil – into the glorious freedom of children of God; from death – into immortality, in order to make us sons of God and to seat us together with Him upon the Throne as His royal children.
O, boundless compassion of God! O, inexpressible wisdom of God! O, great wonder, astounding not only the human mind, but the angelic [mind] as well!
. . .
Source: ‘The Word Became Flesh’, http://www.orthodox.net/nativity/nativity-sjok-2.html, accessed 26 Dec. 2014