The power of God is beyond the conception of man. Just as the being of God and the life of the Blessed Trinity are known to us only through the light vouchsafed us by revelation, so also are His actions equally impenetrable to our gaze, except for His con descension in telling us about Himself. We should really be unable to follow the progress of His power had He not Himself assured us of His intervention and His design in the history of the race. Indeed, the unity of God is so straight and close that it is absolutely and logically necessary to admit that in God there is no distinction between His acts and Himself. His very being and His acts are one: hence His power is as infinite, as limitless, as is His nature. For the same reason, too, I can never look for the cause or motive of His action outside of Himself. If it were possible for Him to find the reason of His actions in what I do, then He could not be all-powerful. It is essential that He should do all things for Himself alone: for a God who was directed by this or that, by what He saw in His creatures, would be changeable and no longer independent. When, then, I say that God is all-powerful, I mean quite simply that His power is commensurate with every possibility; and I am assured that this is true because I realize that His power is identical with His being; and in consequence as the one is infinite, the other must be infinite also.
Yet it might seem as though there were things that He could not do, limits that might be set to His power. He could not, it is obvious, make something that should be at once and from the same point of view both round and square. He could not make Himself or any other thing three in exactly the same sense as He is one, for that would be a sheer impossibility. He is, indeed, Three and One; but One in nature and Three in personality: that is, He is not, in the meaning of the word, Three and One from the same standpoint. Still, even in cases like these which could be multiplied indefinitely, Saint Augustine tells us that it is true to say that God can do everything: for he points out that really it would be more correct to express the apparent contradiction in this way, not that God cannot do the thing, but that the thing itself cannot be done; and the reason that he brings forward for this is most interesting. In all these things, he tells us, God is moved by His intelligence and not by His will: that is to say, there are truths in ethics, in faith, in science, etc., which are true, not because God wants them to be true, but because He knows them to be true. We may put this more clearly perhaps, but less accurately, by saying that some things are wrong not because God has forbidden them, but that He has forbidden them because they are wrong. Thus polygamy is wrong, not in itself but because it has been forbidden; whereas injustice is wrong in itself and is for that reason forbidden by God. Just then, as in these moral cases, certain things cannot be allowed, so in those other instances which seem to limit God's power we see really that it is the contradiction which is opposed by the intelligence of God.
God, then, in a certain sense can be said to be at the mercy of truth. And this is truly so, for God is Truth. He is at the mercy of Himself. He is all-mighty, but he is also Truth, Mercy, Justice: therefore truth, mercy, justice must prevail. The interplay of these great forces is beyond my reason to discover - I cannot find out the limits of each. Humanly speaking, it is difficult to reconcile justice and mercy, truth and charity, wisdom and love: but with Him all these things are one, for they are all Himself. He, in the height of His Godhead, includes all these attributes, and with Him they are in perfect order. So, too, His power is compatible with Truth. Let me take this to a personal point. The whole series of commandments, the articles of faith, are not the choosing of God, but spring from God's own nature. They are all true because God is truth. The faith which, if you will, tyrannizes over me, tyrannizes also over God. I submit to it; and so, if you will, does He, for it is Himself. No doubt my ideas of His power are often at fault. I want this done and that, forgetting, it may be, that God cannot act contrary to His own nature. There are, in that inaccurate sense, limits to the power of God - namely, the limits set by His own being. I have grumbled because I did not see that the very truth of His nature forbade what seemed to me to be necessary for myself or another. Let me then, as always, put myself passively into His hands. He is almighty, but there is also the full domain of truth. With Him, although not with man, Might is Right.
- text taken from Meditations for Layfolk by Father Bede Jarrett, O.P.