1. Beginning, as I now do henceforward, to speak of subjects which cannot altogether be spoken as they are thought, either by any man, or, at any rate, not by myself; although even our very thought, when we think of God the Trinity, falls (as we feel) very far short of Him of whom we think, nor comprehends Him as He is; but He is seen, as it is written, even by those who are so great as was the Apostle Paul, |through a glass and in an enigma:| first, I pray to our Lord God Himself, of whom we ought always to think, and of whom we are not able to think worthily, in praise of whom blessing is at all times to be rendered, and whom no speech is sufficient to declare, that He will grant me both help for understanding and explaining that which I design, and pardon if in anything I offend. For I bear in mind, not only my desire, but also my infirmity. I ask also of my readers to pardon me, where they may perceive me to have had the desire rather than the power to speak, what they either understand better themselves, or fail to understand through the obscurity of my language, just as I myself pardon them what they cannot understand through their own dullness.
2. And we shall mutually pardon one another the more easily, if we know, or at any rate firmly believe and hold, that whatever is said of a nature, unchangeable, invisible and having life absolutely and sufficient to itself, must not be measured after the custom of things visible, and changeable, and mortal, or not self-sufficient. But although we labor, and yet fail, to grasp and know even those things which are within the scope of our corporeal senses, or what we are ourselves in the inner man; yet it is with no shamelessness that faithful piety burns after those divine and unspeakable things which are above: piety, I say, not inflated by the arrogance of its own power, but inflamed by the grace of its Creator and Saviour Himself. For with what understanding can man apprehend God, who does not yet apprehend that very understanding itself of his own, by which he desires to apprehend Him? And if he does already apprehend this, let him carefully consider that there is nothing in his own nature better than it; and let him see whether he can there see any outlines of forms, or brightness of colors, or greatness of space, or distance of parts, or extension of size, or any movements through intervals of place, or any such thing at all. Certainly we find nothing of all this in that, than which we find nothing better in our own nature, that is, in our own intellect, by which we apprehend wisdom according to our capacity. What, therefore, we do not find in that which is our own best, we ought not to seek in Him who is far better than that best of ours; that so we may understand God, if we are able, and as much as we are able, as good without quality, great without quantity, a creator though He lack nothing, ruling but from no position, sustaining all things without |having| them, in His wholeness everywhere, yet without place, eternal without time, making things that are changeable, without change of Himself, and without passion. Whoso thus thinks of God, although he cannot yet find out in all ways what He is, yet piously takes heed, as much as he is able, to think nothing of Him that He is not.