1. The following dissertation concerning the Trinity, as the reader ought to be informed, has been written in order to guard against the sophistries of those who disdain to begin with faith, and are deceived by a crude and perverse love of reason. Now one class of such men endeavor to transfer to things incorporeal and spiritual the ideas they have formed, whether through experience of the bodily senses, or by natural human wit and diligent quickness, or by the aid of art, from things corporeal; so as to seek to measure and conceive of the former by the latter. Others, again, frame whatever sentiments they may have concerning God according to the nature or affections of the human mind; and through this error they govern their discourse, in disputing concerning God, by distorted and fallacious rules. While yet a third class strive indeed to transcend the whole creation, which doubtless is changeable, in order to raise their thought to the unchangeable substance, which is God; but being weighed down by the burden of mortality, whilst they both would seem to know what they do not, and cannot know what they would, preclude themselves from entering the very path of understanding, by an over-bold affirmation of their own presumptuous judgments; choosing rather not to correct their own opinion when it is perverse, than to change that which they have once defended. And, indeed, this is the common disease of all the three classes which I have mentioned, -- viz., both of those who frame their thoughts of God according to things corporeal, and of those who do so according to the spiritual creature, such as is the soul; and of those who neither regard the body nor the spiritual creature, and yet think falsely about God; and are indeed so much the further from the truth, that nothing can be found answering to their conceptions, either in the body, or in the made or created spirit, or in the Creator Himself. For he who thinks, for instance, that God is white or red, is in error; and yet these things are found in the body. Again, he who thinks of God as now forgetting and now remembering, or anything of the same kind, is none the less in error; and yet these things are found in the mind. But he who thinks that God is of such power as to have generated Himself, is so much the more in error, because not only does God not so exist, but neither does the spiritual nor the bodily creature; for there is nothing whatever that generates its own existence.
2. In order, therefore, that the human mind might be purged from falsities of this kind, Holy Scripture, which suits itself to babes has not avoided words drawn from any class of things really existing, through which, as by nourishment, our understanding might rise gradually to things divine and transcendent. For, in speaking of God, it has both used words taken from things corporeal, as when it says, |Hide me under the shadow of Thy wings;| and it has borrowed many things from the spiritual creature, whereby to signify that which indeed is not so, but must needs so be said: as, for instance, |I the Lord thy God am a jealous God;| and, |It repenteth me that I have made man.| But it has drawn no words whatever, whereby to frame either figures of speech or enigmatic sayings, from things which do not exist at all. And hence it is that they who are shut out from the truth by that third kind of error are more mischievously and emptily vain than their fellows; in that they surmise respecting God, what can neither be found in Himself nor in any creature. For divine Scripture is wont to frame, as it were, allurements for children from the things which are found in the creature; whereby, according to their measure, and as it were by steps, the affections of the weak may be moved to seek those things that are above, and to leave those things that are below. But the same Scripture rarely employs those things which are spoken properly of God, and are not found in any creature; as, for instance, that which was said to Moses, |I am that I am;| and, |I Am hath sent me to you.| For since both body and soul also are said in some sense to be, Holy Scripture certainly would not so express itself unless it meant to be understood in some special sense of the term. So, too, that which the Apostle says, |Who only hath immortality.| Since the soul also both is said to be, and is, in a certain manner immortal, Scripture would not say |only hath,| unless because true immortality is unchangeableness; which no creature can possess, since it belongs to the creator alone. So also James says, |Every good gift and every perfect gift is from above, and cometh down from the Father of Lights, with whom is no variableness, neither shadow of turning.| So also David, |Thou shall change them, and they shall be changed; but Thou art the same.|
3. Further, it is difficult to contemplate and fully know the substance of God; who fashions things changeable, yet without any change in Himself, and creates things temporal, yet without any temporal movement in Himself. And it is necessary, therefore, to purge our minds, in order to be able to see ineffably that which is ineffable; whereto not having yet attained, we are to be nourished by faith, and led by such ways as are more suited to our capacity, that we may be rendered apt and able to comprehend it. And hence the Apostle says, that |in Christ indeed are hid all the treasures of wisdom and knowledge;| and yet has commended Him to us, as to babes in Christ, who, although already born again by His grace, yet are still carnal and psychical, not by that divine virtue wherein He is equal to the Father, but by that human infirmity whereby He was crucified. For he says, |I determined not to know anything among you, save Jesus Christ and Him crucified;| and then he continues, |And I was with you in weakness, and in fear, and in much trembling.| And a little after he says to them, |And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ. I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able.| There are some who are angry at language of this kind, and think it is used in slight to themselves, and for the most part prefer rather to believe that they who so speak to them have nothing to say, than that they themselves cannot understand what they have said. And sometimes, indeed, we do allege to them, not certainly that account of the case which they seek in their inquiries about God, -- because neither can they themselves receive it, nor can we perhaps either apprehend or express it, -- but such an account of it as to demonstrate to them how incapable and utterly unfit they are to understand that which they require of us. But they, on their parts, because they do not hear what they desire, think that we are either playing them false in order to conceal our own ignorance, or speaking in malice because we grudge them knowledge; and so go away indignant and perturbed.