Beloved, our Lord Jesus Christ, the eternal creator of all things, today became our Savior by being born of a mother. Of his own will he was born for us today, in time, so that he could lead us to his Father’s eternity. God became human like us so that we might become God.

We sinned and became guilty; God is born as one of us to free us from our guilt. We fell, but God descended; we fell miserably, but God descended mercifully; we fell through pride, God descended with his grace.

—Augustine, Sermon 13 on the Time

Let us announce the coming of our Savior with joy! On Christmas strength took on weakness that weakness might become strong. From his human birth let us come to understand how God emptied himself for our sake.

—Augustine, Sermon 190, 3

Our Savior truly became human, and from this has followed the salvation of humanity as a whole. Our salvation is in no way fictitious, nor does it apply only to the body. The salvation of the whole person, that is, of soul and body, has really been achieved in the Word himself.

Our body has acquired something great through its communion and union with the Word. From being mortal it has been made immortal; though it was a living body it has beome a spiritual one; through it was made from the earth it has passed through the gates of heaven.

—Athanasius, To Epictetus 5-9

God on earth, God among us! No longer the God who gives his law amid flashes of lightning, to the sound of the trumpet on the smoking mountain, within the darkness of a terrifying storm, but the God who speaks gently and with kindness in a human body to his kindred. God in the flesh! It is no longer the God who acts only at particular instants, as in the prophets, but one who completely  assumes our human nature and through his flesh, which is that of our race, lifts all humanity up to him.

God comes in the flesh in order to destroy the death concealed in the flesh. Death reigned till the coming of Christ; but when the saving grace of God appeared…death was swallowed up in this [resurrection] victory, being unable to endure the sojourn of the true Life among us. O, the depth of the goodness of God and of his love for all of us! He is the Lord who has appeared to us, not in his divine form, in order not to terrify us in our weakness, but in the form of a servant, that he might set free what had been reduced to servitude.

Today Adam’s condemnation has bee lifted. We shall no longer say: “You are dust, and to dust you shall return,” but, “United to him who is in heaven, you shall be lifted up to heaven.”

—Basil the Great, Homily for the Birth of Christ

It would be no mistake to call [Christmas] the chief and mother of all holy days. Had Christ not been born of the flesh, he would not have been baptized, which is the theophany or manifestation. Nor would he have been crucified, which is the [Passover]. Nor would he have sent down the Spirit, which is Pentecost. Therefore, just as different rivers arise from a single source, these other feasts [Easter, the Ascension, Pentecost] have their beginnings in the birth of Christ.

—John Chrysostom, On the Incomprehensible Nature of God

Through the light of the Spirit we behold the Son, the splendor of God’s glory, and through the Son, the very stamp of the Father, we are led to him who is the source both of his stamp, who is the Son, and of its seal, who is the Holy Spirit.

—Basil the Great, On the Holy Spirit, 26

Therefore let us hasten to this place [Bethlehem] where for our sake the eternal God was born as a little child!

—Ikos of the Nativity of the Lord

The very Word of God, more ancient than the ages, the invisible, the incomprehensible, the incorporeal, the principle issuing from principle, the light born of light, the source of life and of immortality, the imprint of the divine model, the immutable seal, the perfect image, and the definitive word of the Father proceeds toward his own image, clothes himself with flesh to save the flesh, unites a thinking soul to himself for the sake of my soul so as to purify the like by the like, and assumes all that is human with the exception of sin.

He who is fullness empties himself. He empties himself at the moment of his glory to enable me to share his fullness.

—Gregory of Nazianzus, Discourses 45

It is, therefore, with an unmistakable tenderness that so great a wealth of divine goodness has been poured out on us, dearly beloved. Not only has the usefulness of foregoing examples served in calling us to eternity, but the Truth himself has even “appeared” in a visible body. We ought, then, to celebrate this day of the Lord’s birth with no listless and worldly joy.

—Leo the Great, Sermons 23.5

Our faith is not founded upon empty words; nor are we carried away by mere caprice or beguiled by specious arguments. On the contrary, we put our faith in words spoken by the Word himself at God’s command. God wished to win us back from disobedience, not by using force to reduce us to slavery but by addressing to our free will a call to liberty.

Without protest he endured his passion, he submitted to death and revealed his resurrection. In all these ways he offered his own humanity as the firstfruits of our race to keep us from losing heart when suffering comes our way, and to make us look forward to receiving the same reward as he did, since we know that we possess the same humanity…We shall enter the kingdom of heaven, because while we lived on earth we acknowledged heaven’s King.

—Hippolytus, On the Refutation of All Heresies 10, 33-34

How could he have given himself if he had not worn flesh? He offered his flesh and gave himself for us, in order that undergoing death in it, “He might bring to nothing the one who held the power of death, that is, the devil.” For this reason we continually give thanks in the name of Jesus Christ. We do not bring to nothing the grace which came to us through him. For the coming of the Savior in the flesh has been the ransom and salvation of all creation.

—Athanasius, Letter to Adelphus

It is as if God the Father sent upon the earth a purse full of his mercy. This purse was burst open during the Lord’s passion to pour forth its hidden contents—the price of our redemption. It was only a small purse, but it was very full. As the Scriptures tell us: “A little child has been given to us, but in him who dwells with the fullness of the divine nature.” The fullness of time brought with it the fullness of divinity. God’s Son came in the flesh so that mortals could see and recognize God’s kindness. When God reveals his humanity, his goodness cannot possibly remain hidden…How could he have shown his mercy more clearly than by taking on himself our condition? We should stop thinking of our own sufferings and remember what he has suffered. The lesser he became through his human nature, the greater was his goodness; the more he lowered himself for me, the dearer he is to me…He has given us a most wonderful proof of his goodness by adding humanity to his own divine nature.

—Bernard of Clairvaux, Sermon 1 for Epiphany