Augustine of Hippo

But since I said that the Omnipotent can only not do what he does not will, lest anyone thinks I rashly said that the Omnipotent cannot do anything, the blessed Apostle also said: If we do not believe, he remains faithful, he cannot deny himself. But because he does not will it, he cannot, for he cannot will it. For justice cannot will to do what is unjust, wisdom cannot will what is foolish, nor can truth will what is false. Hence we are admonished that God is omnipotent, not only in what the Apostle says: He cannot deny himself, but in many things he cannot. Behold, I say, and dare to say in his truth, which I do not dare to deny: God the Omnipotent cannot die, cannot change, cannot be deceived, cannot become miserable, cannot be overcome. These and similar things, far be it from the Omnipotent to be able to do. And therefore, not only does the truth show that he is omnipotent because he cannot do these things, but it also compels the truth to state that he is not omnipotent who can do these things. For God is whatever he wills to be; therefore he is eternal, immutable, truthful, blessed, and invincible as he wills to be. Therefore, if he can be what he does not will, he is not omnipotent; but he is omnipotent, therefore he can do whatever he wills. And thus, what he does not will, he cannot be; for which reason he is called omnipotent, because he can do whatever he wills. Of whom the Psalm also says: In heaven and on earth, he has done all that he willed.