Time, according to Augustine, is the process by which our soul is "stretched out" within the temporal so that we experience life events successively. Augustine finds, within time, the key to understanding our relationship with God who exists solely outside of time. Our presence with God during the temporal is as unchangeable as God himself is unchangeable and is made up of the moments that our eyes are focused solely on him. It is all that is temporal and material that passes away and as we meditate on God and abandon our lives to him we find that the influence of time lessens and we are moving progressively upward toward eternity. So, horizontally we experience the duration of time, while vertically we experience the justification, purification and sanctification of our soul moving ever away from sin and toward righteousness in God in moments that are to us an "eternal present."
.... This ongoing search for truth is the vertical constant within the temporal. It is his relationship with and focus on God that will prove to bind him with the eternal and draw him upwards, away from the temporal and into God's eternal present.
... This is where the temporal intersects with the eternal. The way by which we traverse the moments of time and approach the eternity of God, drawn out of darkness and into light ...
.... Time is understood as the horizontal movement of human existence that is constantly in flux between the past, present and future. Augustine's analysis of time leads him to the conclusion that since the past never truly exists and the future has not yet come into existence, all that remains is the present, which is constantly flowing toward non-existence. Because time, as a separate existence of past, present and future, is inexpressible, Augustine proposes that one refer to time as, "three times, a present of things past, a present of things present, a present of things to come." These three exist concurrently in the soul, which dilates to incorporate memories of the past, immediate awareness of the present, and expectation for the future .
Eternity, on the other hand, is defined as the "eternal present" or "eternal day" understood as the Abidingness and unchangeableness of God which "embraces and transcends time." For Augustine, the purpose of time is to be caught up into this "eternal present" to the extent to which we can experience it while still bound by the temporal.
..... Augustine saw that eternity operated within time as an eternal present and, rather than being found through outward searching, it is when one turns the attention of their soul, their "inner eyes," toward God, that they are brought into contact with the Light and the Truth. "It is eternity which hides behind the temporal flow, revealed, if at all, within the instant which we cannot capture." Augustine found himself to be present within eternity when he experienced what he refers to as "light." Often understood in today's context as "enlightenment," the revelatory light, for Augustine, was a source of power from outside of himself that brought wisdom and understanding to his heart. ..... Augustine directly related this illumination as Godly intervention within his temporal time and space and thus understood it to be a small "slice" of eternity. It was in these moments that Augustine understood truth and was imparted wisdom.
..... Memory plays a key role, then, in that the past present of those in darkness is redeemed by the activity of the Lord within each moment. While that person is in darkness, they are blind to it, but once enlightened by God, they become aware of the light that was present all along. Again, here, we witness the presence and activity of God in the lives of all people. ..... So, while on the one hand, the past tends to dissolve into nothingness; it serves, at the same time, to establish salvation. The future, then, promises eschatological redemption, but this redemption is simultaneously defined as the eternally existing present.
For Augustine, eternity is the foundation upon which time is built and sustained. Time is the means by which redemptive history is fulfilled.
...... movement for man within eternity is constant vertical progression toward God who is immovable. It is by this unchanging nature that eternity with God consists of an eternal day. While God has no need to change, man is constantly tossed by the temporal waves of change. When grounded in the immutable truth and light of God and living for nothing but God, however, man can participate in that eternal present. Righteousness is the substance of the eternal present.
Augustine's understanding of eternity is based on the idea that there is nothing lacking in God and nothing that should pass away. God is perfect and remains the same. The temporal serves the eternal in that it is the process by which all that is held in opposition to God's nature is drawn either toward him or flees from him.
You will seek me and find me, when you seek me with all your heart. (Jer 29:13, ESV)
Jesus said to her, “I am the resurrection and the life. Whoever believes in me, though he die, yet shall he live, and everyone who lives and believes in me shall never die. Do you believe this?” (John 11:25-26, ESV)