If anyone, following our train of thought, says, "Good, he can hear", must he not go on to ask, "But can he also answer our prayers?” Or is not the prayer of petition, the call of the creature up to God, in the last analysis a pious trick to elevate man psychologically and to comfort him, because he is seldom capable of higher forms of prayer? Surely the whole thing serves solely to set man in motion somehow or other toward transcendence, although in reality nothing can happen or be changed as a result of his prayers; for what is eternal is eternal, and what is temporal is temporal—no path seems to lead from one to the other. This, too, we cannot consider in detail here, because a very searching critical analysis of the concepts of time and eternity would be required. One would have to investigate their foundations in ancient thought and the synthesis of this thought with the biblical faith, a synthesis whose imperfection lies at the root of modern questioning. One would have to reflect once again on the relationship of scientific and technical thinking to the thinking of faith. These are tasks that go far beyond the scope of this book. So here again, instead of detailed answers, we must settle for an indication of the general direction in which the answer is to be sought.
Modern thinking usually lets itself be guided by the idea that eternity is imprisoned, so to speak, in its unchangeableness; God appears as the prisoner of his eternal plan conceived “before all ages”. “Being” and “becoming” do not mingle. Eternity is thus understood in a purely negative sense as timelessness, as the opposite to time, as something that cannot make its influence felt in time for the simple reason that it would thereby cease to be unchangeable and itself become temporal. Fundamentally these ideas remain the products of a pre-Christian mentality that takes no account of a concept of God that finds utterance in a belief in creation and incarnation. At bottom they take for granted the dualism of antiquity—something that we cannot go into here—and are signs of an intellectual naïveté that looks at God in human terms. For if one thinks that God cannot alter retrospectively what he planned “before” eternity, then unwittingly one is again conceiving eternity in terms of time, with its distinction between “before” and “after”.
But eternity is not the very ancient, which existed before time began, but the entirely other, which is related to every passing age as its today and is really contemporary with it; it is not itself barred off into a “before” and “after”; it is much rather the power of the present in all time. Eternity does not stand by the side of time, quite unrelated to it; it is the creatively supporting power of all time, which encompasses passing time in its own present and thus gives it the ability to be. It is not timelessness but dominion over time. As the Today that is contemporary with all ages, it can also make its influence felt in any age.
-Introduction to Christianity, p 315-7