6 But, again, how can these things [below] be images of those [above], since they are really contrary to them, and can in no respect have sympathy with them? For those things which are contrary to each other may indeed be destructive of those to which they are contrary, but can by no means be their images— as, for instance, water and fire; or, again, light and darkness, and other such things, can never be the images of one another. In like manner, neither can those things which are corruptible and earthly, and of a compound nature, and transitory, be the images of those which, according to these men, are spiritual; unless these very things themselves be allowed to be compound, limited in space, and of a definite shape, and thus no longer spiritual, and diffused, and spreading into vast extent, and incomprehensible.
For they must of necessity be possessed of a definite figure, and confined within certain limits, that they may be true images; and then it is decided that they are not spiritual. If, however, these men maintain that they are spiritual, and diffused, and incomprehensible, how can those things which are possessed of figure, and confined within certain limits, be the images of such as are destitute of figure and incomprehensible?
Source: Adversus haereses (New Advent)