Reply Obj. 3: In creatures, power is the principle not only of action, but likewise of effect. Thus in God the idea of power is retained, inasmuch as it is the principle of an effect; not, however, as it is a principle of action, for this is the divine essence itself; except, perchance, after our manner of understanding, inasmuch as the divine essence, which pre-contains in itself all perfection that exists in created things, can be understood either under the notion of action, or under that of power; as also it is understood under the notion of suppositum possessing nature, and under that of nature. Accordingly the notion of power is retained in God in so far as it is the principle of an effect.
Reply Obj. 4: Power is predicated of God not as something really distinct from His knowledge and will, but as differing from them logically; inasmuch as power implies a notion of a principle putting into execution what the will commands, and what knowledge directs, which three things in God are identified. Or we may say, that the knowledge or will of God, according as it is the effective principle, has the notion of power contained in it. Hence the consideration of the knowledge and will of God precedes the consideration of His power, as the cause precedes the operation and effect. _______________________
SECOND ARTICLE [I, Q. 25, Art. 2]
Whether the Power of God Is Infinite?
Objection 1: It seems that the power of God is not infinite. For everything that is infinite is imperfect according to the Philosopher (Phys. iii, 6). But the power of God is far from imperfect. Therefore it is not infinite.
Obj. 2: Further, every power is made known by its effect; otherwise it would be ineffectual. If, then, the power of God were infinite, it could produce an infinite effect, but this is impossible.
Obj. 3: Further, the Philosopher proves (Phys. viii, 79) that if the power of any corporeal thing were infinite, it would cause instantaneous movement. God, however, does not cause instantaneous movement, but moves the spiritual creature in time, and the corporeal creature in place and time, as Augustine says (Gen. ad lit. 20, 22, 23). Therefore, His power is not infinite.
On the contrary, Hilary says (De Trin. viii), that "God's power is immeasurable. He is the living mighty one." Now everything that is immeasurable is infinite. Therefore the power of God is infinite.
I answer that, As stated above (A. 1), active power exists in God according to the measure in which He is actual. Now His existence is infinite, inasmuch as it is not limited by anything that receives it, as is clear from what has been said, when we discussed the infinity of the divine essence (Q. 7, A. 1). Wherefore, it is necessary that the active power in God should be infinite. For in every agent is it found that the more perfectly an agent has the form by which it acts the greater its power to act. For instance, the hotter a thing is, the greater the power has it to give heat; and it would have infinite power to give heat, were its own heat infinite. Whence, since the divine essence, through which God acts, is infinite, as was shown above (Q. 7, A. 1) it follows that His power likewise is infinite.
Reply Obj. 1: The Philosopher is here speaking of an infinity in regard to matter not limited by any form; and such infinity belongs to quantity. But the divine essence is otherwise, as was shown above (Q. 7, A. 1); and consequently so also His power. It does not follow, therefore, that it is imperfect.