Summa contra Gentiles3.158 Chapter CLVIII. How man is freed from sin

Whereas man cannot return to one of two opposites unless he go away from the other; in order by the aid of grace to return to the state of righteousness, he must withdraw from sin whereby he had abandoned the path of rectitude. And since it is chiefly by his will that man is directed to his ultimate end and turned away from it, it is necessary that he not only withdraw from sin in his external actions, by ceasing to sin, but also that he withdraw by his will, in order to rise from sin by grace. Now man withdraws from sin by his will, in repenting of the past sin, and purposing to avoid it for the future. Therefore in order to rise from sin man must both repent of past sins and purpose to avoid future sins. For did he not propose to sin no more, sin would not, in itself, be contrary to his will. And if he were willing to sin no more without repenting of his past sin, the sin itself that he committed would not be contrary to his will.—Now, the movement of recession from a thing is contrary to the movement of approach, as whitening is contrary to blackening. Hence in withdrawing from sin the will must take the contrary road to that which led it into sin. Now, it was led into sin by the desire and pleasure of things beneath it. Therefore it needs to turn away from sin by certain punishments, whereby it suffers for having sinned: for even as the will was drawn by pleasure to consent to sin, so by punishment it is confirmed in the detestation of sin.

Again. Fear of the whip deters even dumb animals from their greatest delights. Now the man who arises from sin must not only detest his past sin, but also avoid future sin. It is, therefore, right that he should be punished for his sin, that he may be the more strengthened in his purpose to avoid sin.

Besides. The things we acquire with toil and pain are dearer to us, and we are more careful about keeping them: thus men who have enriched themselves by their own labours spend less than those who have received their riches from their parents or in any other way without labour. Now for the man who arises fiom sin it is most necessary that he be most careful, to keep in the state of grace, which he carelessly lost by sinning. Therefore it is fitting that he suffer labour and pain for the sins he committed.

Further. The order of justice demands that punishment be awarded for sin. Now, the wisdom of God’s government appears in the maintenance of order among things. There- 1 Augustine, Qq. Ixxxiii., qu. 36.

fore it belongs to the manifestation of God’s goodness and glory that punishment be the reward of sin. But the sinner by sinning acts against the divinely established order, for he transgresses the laws of God. Therefore it is right that he make compensation by punishing in himself that which had previously sinned: for thus he will be wholly freed of his disorder.

It is clear then that after man has by grace obtained the forgiveness of sin, and been restored to the state of grace, he remains, by virtue of God’s justice, bound to suffer punishment for the sin he has committed. And if he, of his own accord, take this punishment on himself, he is said thereby to satisfy God: inasmuch as with labour and pain he follows the divinely established order by punishing himself for his sin, which same order by sinning he of his own accord had abandoned.—On the other hand if he fails to take this punishment on himself, since the things subject to divine providence cannot remain in disorder, this punishment will be inflicted on him by God. Nor will this punishment come under the name of satisfaction, since it will not be of the sufferer’s choice: but it will be described as purgatorial, because he will be purged, as it were, by another punishing him, and whatever was disorderly in him will be brought back to the right order.—Hence the Apostle says (1 Cor. xi. 31, 32): If we would judge ourselves, we should not be judged. But whilst we are judged, we are chastised by the Lord; that we be not condemned with this world.

We must observe, however, that when the mind turns away from sin, it is possible for its detestation of sin to be so strong, and for it to cling so closely to God, that there remains no obligation to punishment. For, as may be gathered from what has been said, the punishment that one suffers after sin has been forgiven, is necessary in order that the mind may adhere to good more firmly, through being chastised by punishment; for punishment is a kind of medicine; and again that the order of justice may be maintained by the sinner being punished. Now, the love of God suffices to strengthen man’s mind in good, especially if it be vehement; and when the intense detestation of past sin causes great sorrow. Consequently great love of God, and great hatred of past sin remove the need of punishment whether satisfactory or purgatorial: and even if the vehemence be not so great as to exclude all punishment, yet the greater the vehemence, the less punishment will be required.

Now, what we do by our friends, we do apparently by ourselves.-1 because friendship, especially the love of charity, binds two persons together as one. Wherefore as a man can satisfy God by himself, so can he by another; especially when there is urgent need for it. For a man looks upon the punishment which his friend suffers for his sake, as though he suffered it himself: and so he is not without punishment, seeing that he suffers with his suffering friend, and he suffers all the more, according as he is the cause of his friend’s suffering. Again, the love of charity in him who suffers for his friend makes the satisfaction more acceptable to God, than if he suffered for himself: for the former comes of the eagerness of charity, but the latter comes of necessity. Hence we infer that one man may satisfy for another, so long as both remain in charity: wherefore the Apostle says (Gal. vi. 2): Bear ye one another’s burdens, and so ye shall fulfil the law of Christ.