From the writings of Athanasius

He that was the very image of his Father, God the Word from everlasting,  took upon him the form of a servant, and in human shape submitted even to death  for our sakes, and as a sacrifice of propitiation to his Father for us. And, likewise, it was for our sakes and for our advantage that the same person was exalted and glorified; that as our human nature died in his, so it may be raised, exalted and glorified in his [raising]. 

- Athanasius, Orations 1.41, p. 55.  

   
For this purpose, then, the incorporeal and incorruptible and immaterial Word of God entered our world... He entered the world in a new way, stooping to our  level in his love and self-revealing to us. He saw the reasonable race… wasting out of existence, and death reigning over all in corruption…. All this he saw and, pitying our race, moved with compassion for our limitation, unable to endure that death should have the mastery, rather than that his creatures should perish… He took to himself a body, a human body even as our own…. Thus taking a body like our own, because all our bodies were liable to the corruption of death, he surrendered his body to death in place of all, and offered it to the Father. This he did out of sheer love for us, so that in his death all might die, and the law of death thereby be abolished because, when he had fulfilled in his body that for which it was appointed, it was thereafter voided of its power for [humankind]. This he did that he might turn again to incorruption, and make them alive through death by appropriation of his body and by the grace of his resurrection. 

- Athanasius, On the Incarnation 9, in CLF, 62-63

Athanasius of Alexandria (298-373 A.D.) was a bishop of Alexandria (Egypt), in the fourth century.Before reaching the age of 20, Athanasius wrote a treatise entitled On the Incarnation, affirming and explaining that Jesus was both God and Man. In about 319, when Athanasius was a deacon, a presbyter named Arius began teaching that there was a time before God the Father begat Jesus Christ when the latter did not exist. Athanasius responded that the Father's begetting of the Son, or uttering of the Word, was an eternal relationship between them, not an event that took place within time. Thus began catholic Christianity's fight against the heresy of Arianism.  Athanasius fought consistently against Arianism all his life. He accompanied bishop Alexander to the First Council of Nicaea in 325, which council produced the Nicene Creed and anathematized Arius and his followers. On May 9, 328, he succeeded Alexander as bishop of Alexandria. As a result of rises and falls in Arianism's influence, he was banished from Alexandria only to be later restored on at least five separate occasions, perhaps as many as seven. This gave rise to the expression "Athanasius contra mundum" or "Athanasius against the world". During some of his exiles, he spent time with the Desert Fathers, monks and hermits who lived in remote areas of Egypt. In his lifetime he earned the characteristic title of "Father of Orthodoxy". [Biographical sources from Theopedia and New Advent]

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From the writings of Gregory Nazianzen

The Son of God himself, who is before all ages, 
the invisible, the incomprehensible, the bodiless,
 the beginning from the beginning,
 the light from the light, 
source of life and immortality, 
image of the archetype, 
immovable seal, 
unchangeable image, 
the Father's definition and Word, 
he it is who came to his own image and took to himself flesh for the sake of our flesh. 

Then he united himself with an intelligent soul for my soul's sake, purifying like by like. He took to himself all that is human, except sin. He was conceived by the Virgin who was first purified in body and soul by the Spirit. It was necessary both that childbearing be honored and that virginity be honored still more highly. 

He came forth as God with what he had taken to himself. Out of two contraries, flesh and spirit, he made one. The Spirit conferred the godhead on the flesh that received it. 

He who enriches others becomes poor. He took to himself the poverty of my flesh so that I might obtain the riches of his godhead. He who is full empties himself. He emptied himself of his godhead for a brief time so that I might share in his fulness. 

What is this wealth of goodness? What is this mystery that touches me? I received the divine image and I did not keep it. He receives my flesh to save the image and grant immortality to the flesh. This, his second communion with us, is far more marvellous than the first. 

It was necessary that holiness be conferred on man through the humanity God took to himself. In this way, conquering the tyrant by force, he freed us and led us back to himself through his Son, the mediator. The Son brought this about to the honor of the Father to whom, in all things, he is seen to defer. 

The good shepherd, who lays down his life for his sheep, set out after the strayed sheep, on the mountains and hills on which you used to sacrifice. When he found the stray sheep he carried it on those same shoulders that bore the wood of the cross, and brought it back with him to the life above. The brightest of all lights follows the lamp that goes before him. The Word follows the voice in the wilderness. The bridegroom follows the friend of the bridegroom who is making ready for God a special people, cleansing them with water in anticipation of the Spirit.

We needed an incarnate God who would die that we might live. We died with him that we might be cleansed. We rose again with him because we died with him. We were glorified with him because we rose again with him.

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Let us become like Christ, since Christ became like us. Let us become divine for his sake, since he for ours became [human]. He assumed the worst that he  might give us the better; he became poor that we through his poverty might be rich; he took upon himself the form of a servant that we might receive back our liberty; he came down that we might be exalted; he was tempted that we might  conquer; he was dishonored that he might glorify us; he ascended that he might  draw us to himself, who were lying low in the fall of sin. Let us give all, offer all, to him who gave himself a ransom and reconciliation for us. 

- Gregory Nazianzen, Orationes 1.5; quoted in Torrance, op. cit, 180-181

Gregory of Nazianzen (330-389), also know as Gregory of Nazianzus and Gregory the Theologian, was a 4th century bishop (330-389) who came from a family of distinguished church leaders and teachers. While studying in Athens, he became a close friend of Basil the Great, who was also studying there at the time. They returned to their native Cappadocia (now Eastern Turkey) to serve the Lord. Basil became a monk and Gregory, who preferred a life of solitude, was forcibly persuaded by his father to be ordained a presbyter so he could assist in the care of the local Christians in Cappadocia. Gregory described his father’s decision as an “act of tyranny” because Gregory wanted to live a solitary life as an ascetic monk. With Basil’s wise counsel, Gregory nonetheless embraced the life of priestly service.  During the Arian controversy when many teachers contested the full divinity of Christ, both Gregory and Basil took up the pen in defense of the true doctrine of Christ’s divinity. In 381 he presided over the First Ecumenical Council of Constantinople which completed the creed that is commonly called today the Nicene Creed. He taught with such clarity and depth that he became known simply as “the theologian.” During his time as bishop of Constantinople, Gregory encountered fierce opposition from the Arians, but his sermons on the Trinity and the Incarnation won him increasing respect and renown, and even Jerome came in from his desert to hear him.  After a period of troubling work, Gregory resigned and retired to the solitude of the desert, spending his last years contentedly in study, writing, and ascetical practices.