John of Damascus: Exposition of the Orthodox Faith 6Concerning the Word and the Son of God: a reasoned proof.

So then this one and only God is not Wordless. And possessing the Word, He will have it not as without a subsistence, nor as having had a beginning, nor as destined to cease to be. For there never was a time when God was not Word: but He ever possesses His own Word, begotten of Himself, not, as our word is, without a subsistence and dissolving into air, but having a subsistence in Him and life and perfection, not proceeding out of Himself but ever existing within Himself. For where could it be, if it were to go outside Him? For inasmuch as our nature is perishable and easily dissolved, our word is also without subsistence. But since God is everlasting and perfect, He will have His Word subsistent in Him, and everlasting and living, and possessed of all the attributes of the Begetter. For just as our word, proceeding as it does out of the mind, is neither wholly identical with the mind nor utterly diverse from it (for so far as it proceeds out of the mind it is different from it, while so far as it reveals the mind, it is no longer absolutely diverse from the mind, but being one in nature with the mind, it is yet to the subject diverse from it), so in the same manner also the Word of God in its independent subsistence is differentiated from Him from Whom it derives its subsistence: but inasmuch as it displays in itself the same attributes as are seen in God, it is of the same nature as God. For just as absolute perfection is contemplated in the Father, so also is it contemplated in the Word that is begotten of Him.