15 For you will plead that a word is the sound of a voice; that it is a naming of things, an utterance of thoughts. This Word was with God, and was in the beginning; the expression of the eternal Thinker's thoughts must be eternal. For the present I will give you a brief answer of my own on the fisherman's behalf, till we see what defence he has to make for his own simplicity. The nature, then, of a word is that it is first a potentiality, afterwards a past event; an existing thing only while it is being heard.
How can we say, In the beginning was the Word, when a word neither exists before, nor lives after, a definite point of time? Can we even say that there is a point of time in which a word exists? Not only are the words in a speaker's mouth non-existent until they are spoken, and perished the instant they are uttered, but even in the moment of utterance there is a change from the sound which commences to that which ends a word. Such is the reply that suggests itself to me as a bystander.
But your opponent the Fisherman has an answer of his own. He will begin by reproving you for your inattention. Even though your unpractised ear failed to catch the first clause, In the beginning was the Word, why complain of the next, And the Word was with God? Was it And the Word was in God that you heard—the dictum of some profound philosophy? Or is it that your provincial dialect makes no distinction between in and with? The assertion is that Which was in the beginning was with, not in, Another.
But I will not argue from the beginning of the sentence; the sequel can take care of itself. Hear now the rank and the name of the Word:— And the Word was God. Your plea that the Word is the sound of a voice, the utterance of a thought, falls to the ground. The Word is a reality, not a sound, a Being, not a speech, God, not a nonentity.
Source: On the Trinity (New Advent)