I've mentioned what I believe is the Athanasian Revolution in other posts. This is the fundamental shift where a more properly Biblical description of the God-World relationship defeated Hellenistic metaphysics. I call it Athanasian because it was Athanasius, in his battles with the Arians, that most perfectly marked the move. It didn't begin with Athanasius, and it didn't end with him. In some ways, the Revolution has been constantly attacked and undermined, and remains a dormant, but recurring, source of energy for renewed Christians to attack perversions in theological practice.
I would summarize this in a double move:
1) The emphasis on the radical disconnect and otherness between God and Creation. God is eternal, creation came into being from nothing. This is the essence of the creatio ex nihilo. Creatures are separated by an infinite gulf between them and God. He is Wholly Other. There is nothing alike, and Man cannot reason from creation to understand greater principles
2) But as implicit in the above, God does not relate to Creation as Other, but as Creator. Unless we are willing to say God somehow changed, that is He had a new idea and then created it (or more radically, He had the idea of creation itself), then we somehow have to reckon the concept of creation as an eternal, but unactualized idea, in the mind of God. Thus, even as creation is ever distinct from God, it is not alien to Him.
These two moves undermine the Middle and Neo Platonic syntheses of Hellenistic philosophy. This is the destruction of Chain-of-Being metaphysics which always threatens to recur, verging towards a kind of panentheism. Creation is radically different from God, so much so that Creation going into nothing is not merely a slide on the Chain, but a real defeat of God's creative work, a serious threat. It also explains God's redemption not in terms of a predestined magnetism of all things returning to the source, but as a radical act of love and compassion on what is fundamentally not-God to fulfill its purpose in bearing God's glory.
One place where Athanasius reveals this mode of thinking is when he says the Arians are utterly absurd for holding a non-eternal Christ who is the source of creation (Contra Arianos, 2:2). Arius had bit the bullet and said there was a time when God was not Creator, but Asterius, his disciple, tried to rectify this oddity by claiming that God was indeed Creator, but this Creatorship was in the potentiality of the World being created. However, Athanasius claims, the Bible consistently ascribes the creation of the world to Christ, the Word of God by which all things were made. So how can Creation be an eternal quality, but the means of God creating it was not eternal? How can creation exist, and creativity not exist? If the latter doesn't exist, then the former can certainly not exist, because the idea of creation, and creating, cannot exist without creativity. For Athansius, the Arians postulate a mindless god, who is sterile and barren, and thus certainly not God.
The argument is for the eternity of Christ, the Word of God, but it does more than this. It also highlights a primitive essence-energies distinction which is key to Eastern Orthodox theology (and I think a necessity in plainly Christian theology), but one in which Christ is given a certain primacy that later theological elaborations can obscure. However, if the creative energies of God are situated in Christ, the Word of God, who is the agent of creation, then we see that Christ holds them together in His own Person and Being. This is, precisely, what Maximus the Confessor gets right in his discussion of Logos/logoi.
In other words, if God is truly Creator, He is eternally Creator, unless we are to say God changes. However, this Creatorship is potentiality, not necessity. This is as the Arian Asterius says, against Origen's seeming conclusion that the world must somehow be eternal (this was a constant problem among Medieval theologians who read Plato and Aristotle). However, this potentiality necessitates an actual potency, the eternal, and fecund, Word of God. Thus, we can say Christ is Eternal, and thus God, creation is not eternal, and God's status as Creator is eternal, without it necessitating an eternal world.
This is all argumentation for how we, as Christians, declare in the Gospel that the eternal God, in His love and compassion for the warped things He made, sent His Son into the world, the Eternal Word of God who was with God and is God, to save and redeem. The Christ-event utterly overthrows Hellenistic philosophy and baffles it, and yet it makes a certain sense within the parameters of a revealed logic. It is a mystery unveiled to us, that angels, through the ages, had desired to look into. This is the recovery of a Biblical way of thinking applied to how we understand the rudiments of how and why God conducts His saving mission for us.