Reply Obj. 2: The power of a univocal agent is wholly manifested in its effect. The generative power of man, for example, is not able to do more than beget man. But the power of a non-univocal agent does not wholly manifest itself in the production of its effect: as, for example, the power of the sun does not wholly manifest itself in the production of an animal generated from putrefaction. Now it is clear that God is not a univocal agent. For nothing agrees with Him either in species or in genus, as was shown above (Q. 3, A. 5; Q. 4, A. 3). Whence it follows that His effect is always less than His power. It is not necessary, therefore, that the infinite power of God should be manifested so as to produce an infinite effect. Yet even if it were to produce no effect, the power of God would not be ineffectual; because a thing is ineffectual which is ordained towards an end to which it does not attain. But the power of God is not ordered toward its effect as towards an end; rather, it is the end of the effect produced by it.
Reply Obj. 3: The Philosopher (Phys. viii, 79) proves that if a body had infinite power, it would cause a non-temporal movement. And he shows that the power of the mover of heaven is infinite, because it can move in an infinite time. It remains, therefore, according to his reckoning, that the infinite power of a body, if such existed, would move without time; not, however, the power of an incorporeal mover. The reason of this is that one body moving another is a univocal agent; wherefore it follows that the whole power of the agent is made known in its motion. Since then the greater the power of a moving body, the more quickly does it move; the necessary conclusion is that if its power were infinite, it would move beyond comparison faster, and this is to move without time. An incorporeal mover, however, is not a univocal agent; whence it is not necessary that the whole of its power should be manifested in motion, so as to move without time; and especially since it moves in accordance with the disposition of its will. _______________________
THIRD ARTICLE [I, Q. 25, Art. 3]
Whether God Is Omnipotent?
Objection 1: It seems that God is not omnipotent. For movement and passiveness belong to everything. But this is impossible with God, for He is immovable, as was said above (Q. 2, A. 3). Therefore He is not omnipotent.
Obj. 2: Further, sin is an act of some kind. But God cannot sin, nor "deny Himself" as it is said in 2 Tim. 2:13. Therefore He is not omnipotent.
Obj. 3: Further, it is said of God that He manifests His omnipotence "especially by sparing and having mercy" [*Collect, 10th Sunday after Pentecost]. Therefore the greatest act possible to the divine power is to spare and have mercy. There are things much greater, however, than sparing and having mercy; for example, to create another world, and the like. Therefore God is not omnipotent.
Obj. 4: Further, upon the text, "God hath made foolish the wisdom of this world" (1 Cor. 1:20), a gloss says: "God hath made the wisdom of this world foolish [*Vulg.: 'Hath not God', etc.] by showing those things to be possible which it judges to be impossible." Whence it would seem that nothing is to be judged possible or impossible in reference to inferior causes, as the wisdom of this world judges them; but in reference to the divine power. If God, then, were omnipotent, all things would be possible; nothing, therefore impossible. But if we take away the impossible, then we destroy also the necessary; for what necessarily exists is impossible not to exist. Therefore there would be nothing at all that is necessary in things if God were omnipotent. But this is an impossibility. Therefore God is not omnipotent.
On the contrary, It is said: "No word shall be impossible with God" (Luke 1:37).
I answer that, All confess that God is omnipotent; but it seems difficult to explain in what His omnipotence precisely consists: for there may be doubt as to the precise meaning of the word 'all' when we say that God can do all things. If, however, we consider the matter aright, since power is said in reference to possible things, this phrase, "God can do all things," is rightly understood to mean that God can do all things that are possible; and for this reason He is said to be omnipotent. Now according to the Philosopher (Metaph. v, 17), a thing is said to be possible in two ways. First in relation to some power, thus whatever is subject to human power is said to be possible to man. Secondly absolutely, on account of the relation in which the very terms stand to each other. Now God cannot be said to be omnipotent through being able to do all things that are possible to created nature; for the divine power extends farther than that. If, however, we were to say that God is omnipotent because He can do all things that are possible to His power, there would be a vicious circle in explaining the nature of His power. For this would be saying nothing else but that God is omnipotent, because He can do all that He is able to do.