Gregory Nazianzen on the Problem of Trinitarian Analogies
"I have very carefully considered this matter in my own mind, and have looked at it in every point of view, in order to find some illustration of this most important subject, but I have been unable to discover any thing on earth with which to compare the nature of the Godhead. For even if I did happen upon some tiny likeness it escaped me for the most part, and left me down below with my example. I picture to myself an eye*, a fountain, a river, as others have done before, to see if the first might be analogous to the Father, the second to the Son, and the third to the Holy Ghost. For in these there is no distinction in time, nor are they torn away from their connexion with each other, though they seem to be parted by three personalities. But I was afraid in the first place that I should present a flow in the Godhead, incapable of standing still; and secondly that by this figure a numerical unity would be introduced.For the eye and the spring and the river are numerically one, though in different forms." St. Gregory Nazianzen, Oration 31, Chapter 31, emphasis mine. *note: eye = source
Hmm, I wonder what Greg would think of the Cerberus analogy.