Time and Eternity: the Christian Conception of Time
The City of God, Book XII, cc. 16 and 17
16. I own that I do not know what ages passed before the human race was created, yet I have no doubt that no created thing is co-eternal with the Creator. But even the apostle speaks of time as eternal, and this with reference, not to the future, but, which is more surprising, to the past. For he says, In hope of eternal life, which God that cannot lie promised before the eternal times, but has in due times manifested His word. You see he says that in the past there have been eternal times, which, however, were not co-eternal with God.
And since God before these eternal times not only existed, but also, promised life eternal, which He manifested in its own times (that is to say, in due times), what else is this than His word? For this is life eternal. But then, how did He promise; for the promise was made to men, and yet they had no existence before eternal times? Does this not mean that, in His own eternity, and in His co-eternal word, that which was to be in its own time was already predestined and fixed?
17. Of this, too, I have no doubt, that before the first man was created, there never had been a man at all, neither this same man himself recurring by I know not what cycles, and having made I know not how many revolutions, nor any other of similar nature. From this belief I am not frightened by philosophical arguments, among which that is reckoned the most acute which is founded on the assertion that the infinite cannot be comprehended by any mode of knowledge. Consequently, they argue, God has in his own mind finite conceptions of all finite things which He makes. Now it cannot be supposed that His goodness was ever idle; for if it were, there should be ascribed to Him an awakening to activity in time, from a past eternity of inactivity, as if He repented of an idleness that had no beginning, and proceeded, therefore, to make a beginning of work.
This being the case, they say it must be that the same things are always repeated, and that as they pass, so they are destined always to return, whether amidst all these changes the world remains the same—the world which has always been, and yet was created,— or that the world in these revolutions is perpetually dying out and being renewed; otherwise, if we point to a time when the works of God were begun, it would be believed that He considered His past eternal leisure to be inert and indolent, and therefore condemned and altered it as displeasing to Himself. Now if God is supposed to have been indeed always making temporal things, but different from one another, and one after the other, so, that He thus came at last to make man, whom He had never made before, then it may seem that He made man not with knowledge (for they suppose no knowledge can comprehend the infinite succession of creatures), but at the dictate of the hour, as it struck him at the moment, with a sudden and accidental change of mind.
On the other hand, say they, if those cycles be admitted, and if we suppose that the same temporal things are repeated, while the world either remains identical through all these rotations, or else dies away and is renewed, then there is ascribed to God neither the slothful ease of a past eternity, nor a rash and unforeseen creation. And if the same things be not thus repeated in cycles, then they cannot by any science or prescience be comprehended in their endless diversity. Even though reason could not refute, faith would smile at these argumentations, with which the godless endeavor to turn our simple piety from the right way, that we may walk with them in a circle. But by the help of the Lord our God, even reason, and that readily enough, shatters these revolving circles which conjecture frames.
For that which specially leads these men astray to refer their own circles to the straight path of truth, is, that they measure by their own human, changeable, and narrow intellect the divine mind, which is absolutely unchangeable, infinitely capacious, and without succession of thought, counting all things without number. So that saying of the apostle comes true of them, for, "comparing themselves with themselves, they do not understand". For because they do, in virtue of a new purpose, whatever new thing has occurred to them to be done (their minds being changeable), they conclude it is so with God; and thus compare, not God—for they cannot conceive God, but think of one like themselves when they think of Him—not God, but themselves, and not with Him, but with themselves. For our part, we dare not believe that God is affected in one way when He works, in another when He rests. Indeed, to say that He is affected at all, is an abuse of language, since it implies that there comes to be something in His nature which was not there before.
For he who is affected is acted upon, and whatever is acted upon is changeable. His leisure, therefore, is no laziness, indolence, inactivity; as in His work is no labor, effort, industry. He can act while He reposes, and repose while He acts. He can begin a new work with (not a new, but) an eternal design; and what He has not made before, He does not now begin to make because He repents of His former repose. But when one speaks of His former repose and subsequent operation (and I know not how men can understand these things), this former and subsequent are applied only to the things created, which formerly did not exist, and subsequently came into existence.
But in God the former purpose is not altered and obliterated by the subsequent and different purpose, but by one and the same eternal and unchangeable will He effected regarding the things He created, both that formerly, so long as they were not, they should not be, and that subsequently, when they began to be, they should come into existence. And thus, perhaps, He would show, in a very striking way, to those who have eyes for such things, how independent He is of what He makes, and how it is of His own gratuitous goodness He creates, since from eternity He dwelt without creatures in no less perfect a blessedness.
The City of God, Book XII, cc. 16 and 17.
Source of the english test: http://www.newadvent.org/fathers/120112.htm