The Enchiridion

Hence we must inquire in what sense is said of God what the apostle has mostly truly said: “Who will have all men to be saved.” For, as a matter of fact, not all, nor even a majority, are saved: so that it would seem that what God wills is not done, man's will interfering with, and hindering the will of God. When we ask the reason why all men are not saved, the ordinary answer is: “Because men themselves are not willing.” This, indeed cannot be said of infants, for it is not in their power either to will or not to will.

But if we could attribute to their will the childish movements they make at baptism, when they make all the resistance they can, we should say that even they are not willing to be saved. Our Lord says plainly, however, in the Gospel, when upbraiding the impious city: “How often would I have gathered your children together, even as a hen gathers her chickens under her wings, and you would not!” as if the will of God had been overcome by the will of men, and when the weakest stood in the way with their want of will, the will of the strongest could not be carried out.

And where is that omnipotence which has done all that it pleased on earth and in heaven, if God willed to gather together the children of Jerusalem, and did not accomplish it? Or rather, Jerusalem was not willing that her children should be gathered together? But even though she was unwilling, He gathered together as many of her children as He wished: for He does not will some things and do them, and will others and do them not; but “He has done all that He pleased in heaven and in earth.”