10 God, subsisting alone, and having nothing contemporaneous with Himself, determined to create the world. And conceiving the world in mind, and willing and uttering the word, He made it; and straightway it appeared, formed as it had pleased Him. For us, then, it is sufficient simply to know that there was nothing contemporaneous with God. Beside Him there was nothing; but He, while existing alone, yet existed in plurality. For He was neither without reason, nor wisdom, nor power, nor counsel And all things were in Him, and He was the All.
When He willed, and as He willed, He manifested His word in the times determined by Him, and by Him He made all things. When He wills, He does; and when He thinks, He executes; and when He speaks, He manifests; when He fashions, He contrives in wisdom. For all things that are made He forms by reason and wisdom— creating them in reason, and arranging them in wisdom. He made them, then, as He pleased, for He was God. And as the Author, and fellow-Counsellor, and Framer of the things that are in formation, He begot the Word; and as He bears this Word in Himself, and that, too, as (yet) invisible to the world which is created, He makes Him visible; (and) uttering the voice first, and begetting Him as Light of Light, He set Him forth to the world as its Lord, (and) His own mind; and whereas He was visible formerly to Himself alone, and invisible to the world which is made, He makes Him visible in order that the world might see Him in His manifestation, and be capable of being saved.
Source: Against the Heresy of Noetus (New Advent)