The perfection of the effect derives from the perfection (1) of the cause. If perfection is not impossible for Him, it must necessarily belong to Him. For if it were merely possible—neither necessary nor impossible—its being established for Him would depend upon another; and whatever is such cannot be necessary in existence through itself. Thus, every perfection possible for Him is necessary for Him.
[The Impossibility of the Necessary Being’s Product Being Coeternal with Him]
It is impossible (2) for what He produces to coexist with Him from eternity, for several reasons. The first is that what He produces necessarily entails temporal events and is never free of them. Whatever entails temporal events cannot (3) be the effect of a complete, beginningless cause, for no part of the effect of a complete, beginningless cause can be delayed (4). If any part of it were delayed (5), it would be a cause (6) potentially rather than actually, and would depend upon something separate from itself in order to produce it; and that is impossible. It follows, therefore, that what He produces can proceed from Him only one thing (7) after another (8). Everything He produces thus comes into being after not having existed. Moreover, if it coexisted with Him in eternity, that would preclude (9) its being produced by Him, for it is rationally impossible for something to be produced while coexisting with its producer.
Nor can any particular existent be conceived as a complete cause of an effect distinct from itself