Thomas Aquinas

“ According to Augustine, the work of creation belongs to the production of formless matter, and of the formless spiritual nature, both of which are outside of time, as he himself says (Confess. xii, 12) . Thus, then, the creation of either is set down before there was any day. But it may also be said, following other holy writers, that the works of distinction and adornment imply certain changes in the creature which are measurable by time; whereas the work of creation lies only in the Divine act producing the substance of beings instantaneously. ”

“ In creation the Person of the Father is indicated by God the Creator, the Person of the Son by the beginning, in which He created, and the Person of the Holy Ghost by the Spirit that moved over the waters. ”

“ But according to the holy writers, the Spirit of the Lord signifies the Holy Ghost, Who is said to "move over the water"---that is to say, over what Augustine holds to mean formless matter, lest it should be supposed that God loved of necessity the works He was to produce, as though He stood in need of them. For love of that kind is subject to, not superior to, the object of love. ”