For no sooner do we begin to live in this dying body, than we begin to move ceaselessly towards death. For in the whole course of this life (if life we must call it) its mutability tends towards death. Certainly there is no one who is not nearer it this year than last year, and tomorrow than today, and today than yesterday, and a short while hence than now, and now than a short while ago. For whatever time we live is deducted from our whole term of life, and that which remains is daily becoming less and less; so that our whole life is nothing but a race towards death, in which no one is allowed to stand still for a little space, or to go somewhat more slowly, but all are driven forwards with an impartial movement, and with equal rapidity. For he whose life is short spends a day no more swiftly than he whose life is longer. But while the equal moments are impartially snatched from both, the one has a nearer and the other a more remote goal to reach with this their equal speed. It is one thing to make a longer journey, and another to walk more slowly. He, therefore, who spends longer time on his way to death does not proceed at a more leisurely pace, but goes over more ground.
equal moments, equal speed
Further, if every man begins to die, that is, is in death, as soon as death has begun to show itself in him (by taking away life, to wit; for when life is all taken away, the man will be then not in death, but after death), then he begins to die so soon as he begins to live. For what else is going on in all his days, hours, and moments, until this slow-working death is fully consummated? And then comes the time after death, instead of that in which life was being withdrawn, and which we called being in death. Man, then, is never in life from the moment he dwells in this dying rather than living body—if, at least, he cannot be in life and death at once. Or rather, shall we say, he is in both?— in life, namely, which he lives till all is consumed; but in death also, which he dies as his life is consumed? For if he is not in life, what is it which is consumed till all be gone? And if he is not in death, what is this consumption itself? For when the whole of life has been consumed, the expression after death would be meaningless, had that consumption not been death. And if, when it has all been consumed, a man is not in death but after death, when is he in death unless when life is being consumed away?
-St. Augustine, City of God, Book XIII, chapter 10