5. Thus then there is shown forth One God, the Father, not made, invisible, creator of all things; above whom there is no other God, and after whom there is no other God. And, since God is rational, therefore by (the) Word He created the things that were made; and God is Spirit, and by (the) Spirit He adorned all things: as also the prophet says: By the word of the Lord were the heavens established, and by his spirit all their power. Since then the Word establishes, that is to say, gives body and grants the reality of being, and the Spirit gives order and form to the diversity of the powers; rightly and fittingly is the Word called the Son, and the Spirit the Wisdom of God. Well also does Paul His apostle say: One God, the Father, who is over all and through all and in us all. For over all is the Father; and through all is the Son, for through Him all things were made by the Father; and in us all is the Spirit, who cries Abba Father, and fashions man into the likeness of God. Now the Spirit shows forth the Word, and therefore the prophets announced the Son of God; and the Word utters the Spirit, and therefore is Himself the announcer of the prophets, and leads and draws man to the Father.
Commentary · The Demonstration of the Apostolic Preaching, Section 5 · Original source