Gregory of Nyssa

Instead of speaking of him [God the Father] as "ungenerated," it is permissible to call him the "First Cause" or "Father of the Only-Begotten," or to speak of him as "existing without cause," and many such expressions that lead to the same thought. In that case Eunomius confirms our doctrines by the very arguments in which he brings charges that we do not know any name indicative of the divine nature. We are taught the fact of its existence, while we assert that a name of such breath as to include the unspeakable and infinite nature either does not exist at all or at any rate is unknown to us. Let him then abandon his usual fictive language, and show us the names that signify the real meanings and then proceed further to divide the subject by the divergence of their names. But as long as the statement of the Scripture is correct that Abraham and Moses were not capable of the knowledge of the name, and that "no one has seen God at any time," and that "no one has seen him, nor can see," and that the light around him is unapproachable and "there is no end of his greatness," so long can we say and believe these things. This is similar to an argument that promises any comprehension and expression of the infinite nature by means of the meaning of names to one who thinks that he can enclose the whole sea in his own hand! Just as the hollow of one's hand is comparable to the entire depth of the sea, so is all the power of language comparable to that nature that is unspeakable and incomprehensible.