It is now generally recognised that the stellar universe, inconceivably vast as are its dimensions, nevertheless is limited in space: whence it may plausibly be argued to be limited in duration also, in the sense of not having existed from eternity. Where there is no matter, neither is there any place, nor any marked out extension: but there is an unfulfilled extensibility, or absolute space, which is founded upon the immensity of God. In like manner, when as yet creatures were not, there was no time, as there was no motion, nor any body to move. There was only a potentiality of time, founded upon the eternity of God. Creatures have been from the beginning of time, as Plato saw (Timaeus 37, 38), but they cannot be argued to have been from eternity, eternally coexistent with God, unless they be argued to be necessary to God, in which case they cease to be creatures.
Of God and His Creatures: 2.31