The Confessions And Letters Of St by St. Augustine
Chapter XI.--That the Symbols of the Trinity in Man, to Be, to Know, and to Will, are Never Thoroughly Examined.
12. Which of us understandeth the Almighty Trinity? And yet which speaketh not of It, if indeed it be It? Rare is that soul which, while it speaketh of It, knows what it speaketh of. And they contend and strive, but no one without peace seeth that vision. I could wish that men would consider these three things that are in themselves. These three are far other than the Trinity; but I speak of things in which they may exercise and prove themselves, and feel how far other they be. But the three things I speak of are, To Be, to Know, and to Will. For I Am, and I Know, and I Will; I Am Knowing and Willing; and I Know myself to Be and to Will; and I Will to Be and to Know. In these three, therefore, let him who can see how inseparable a life there is, -- even one life, one mind, and one essence; finally, how inseparable is the distinction, and yet a distinction. Surely a man hath it before him; let him look into himself, and see, and tell me. But when he discovers and can say anything of these, let him not then think that he has discovered that which is above these Unchangeable, which Is unchangeably, and Knows unchangeably, and Wills unchangeably. And whether on account of these three there is also, where they are, a Trinity; or whether these three be in Each, so that the three belong to Each; or whether both ways at once, wondrously, simply, and vet diversely, in Itself a limit unto Itself, yet illimitable; whereby It is, and is known unto Itself, and sufficeth to Itself, unchangeably the Self-same, by the abundant magnitude of its Unity, -- who can readily conceive? Who in any wise express it? Who in any way rashly pronounce thereon?