The Divine Institutes

If He is able to pardon, He is therefore able also to be angry. Why, then, some one will say, does it often occur, that they who sin are prosperous, and they who live piously are wretched? Because fugitives and disinherited persons live without restraint, and they who are under the discipline of a father or master live in a more strict and frugal manner. For virtue is proved and fixed by means of ills; vices by means of pleasure. Nor, however, ought he who sins to hope for lasting impunity, because there is no lasting happiness.

…as the not inelegant poet says. It is the end which proves happiness, and no one is able to escape the judgment of God, either when alive or after death. For He has the power both to cast down the living from on high, and to punish the dead with eternal torments. Nay, he says, if God is angry, He ought to have inflicted vengeance at once, and to have punished every one according to his desert. But (it is replied) if He had done this, no one would survive. For there is no one who offends in no respect, and there are many things which excite to the commission of sin—age, intemperance, want, opportunity, reward. To such an extent is the frailty of the flesh with which we are clothed liable to sin, that unless God were indulgent to this necessity, perhaps too few would live. On this account He is most patient, and restrains His anger. For because there is in Him perfect virtue, it follows of necessity that His patience also is perfect, which is itself also a virtue. How many men, from having been sinners, have afterwards become righteous; from being injurious, have become good; from being wicked, have become temperate! How many who were in early life base, and condemned by the judgment of all, afterwards have turned out praiseworthy? But it is plain that this could not happen if punishment followed every offence.

The public laws condemn those who are manifestly guilty; but there are great numbers whose offences are concealed, great numbers who restrain the accuser either by entreaties or by reward, great numbers who elude justice by favour or influence. But if the divine censure should condemn all those who escape the punishment of men, there would be few or even no men on the earth. In short, even that one reason for destroying the human race might have been a just one, that men, despising the living God, pay divine honour to earthly and frail images, as though they were of heaven, adoring works made by human hands. And though God their Creator made them of elevated countenance and upright figure, and raised them to the contemplation of the heaven and the knowledge of God, they have preferred, like cattle, to bend themselves to the earth. For he is low, and curved, and bent downward, who, turning away from the sight of heaven and God his Father, worships things of the earth, which he ought to have trodden upon, that is, things made and fashioned from earth. Therefore, amidst such great impiety and such great sins of men, the forbearance of God attains this object, that men, condemning the errors of their past life, correct themselves. In short, there are many who are just and good; and these, having laid aside the worship of earthly things, acknowledge the majesty of the one and only God. But though the forbearance of God is very great and most useful; yet, although late, He punishes the guilty, and does not suffer them to proceed further, when He sees that they are incorrigible.