Some ignorant people probably think that he wishes to establish the fable of the Greeks, which they have somehow learned to honor, deceiving and being deceived (2 Tim 3:13). For by inventing according to their own whim some fate and destiny, and by ascribing to these nonexistent things power over our circumstances, they deprive man of what is most fitting to him. That is the necessity of living freely, with an unconstrained and voluntary inclination toward the choice of what ought to be done.
By subjecting those who are in this life, as though by necessity, to the limits and lots they define, they harm them beyond measure. For according to them, if someone turns toward what he ought not, he will be unable to escape the beckoning of fate, even if perhaps he does not wish it. Indeed, no prudent man at all will be able to blame him, even if he is plainly sinning. For if he is convicted of having done what was unavoidable and done against his will, this will necessarily be outside accusation and punishment.
On the other hand, it would be prudent not to praise too greatly a virtuous and honorable man. What of it, if he became such not by his own will, but was brought to this by the beckonings of another? Or rather, fate set before him an irresistible predestination.
Therefore it is completely unfitting to think that the teacher of the most beautiful doctrines was carried away by the subtleties of the Greeks. Nor should we suppose that he who became for us the steward of the divine mysteries followed their absurdities, even though he says: “For I do not understand what I do; for I do not do what I will, but what I hate, that I do.”
Even if someone should insist on this and decide to think that the Apostle ascribed power over our circumstances to fate and destiny, would he not ask him with full justification, speaking somewhat as follows? “If by harsh and unbearable predeterminations we are bound to what must or must not be done, and have become masters of nothing, but instead yield even what we refrain from by intention to others as possessing us. Why then did you yourself write to us: ‘Do you not know, brethren, for I speak to those who know the law, that the law has authority over a man as long as he lives?’ (Rom 7:1).”
Therefore the law in some way has authority over the living. In those who have died, it will necessarily be inactive. It is not established for them. How could it be? It is established for those who pass their life in the body. It crowns with praises the one who has become practiced in attaining good repute, but it assigns punishment to the impious.
How, then, will the Lawgiver be a righteous Judge when He punishes those who sin, if they fell into this against their will by the compulsion of fate? Moreover, why was the law established at all? The law justly determines punishment for those who have power to do what they wish. Though they had the possibility of gaining approval by giving the mind to good deeds, they preferred the shameful and reckoned what the law condemns to be better.
But the ordinance of the law is useless, I think, for those on whom the yoke of predestination hangs, and who are always turned wherever those ruling them consent. Yet would it not be true to say that He Who knows all things would not have imposed on us the burden of the law, which precisely defines what is pleasing to Him and directs us toward what is profitable, if He knew that we were caught in the nets of fate?
Let the opponents either say that God did not know this, or, if they have resolved to think rightly, let them be exceedingly afraid to proclaim ignorance of the ineffable glory. But they affirm that He established the law, and they clearly confess that He appointed punishments for those who sin. He certainly knows that nothing prevents man from passing his life according to free intention and from being able, by voluntary impulses, to direct himself wherever he wishes. For this reason the divine Paul said that the law has authority over a man as long as he lives.
Therefore he does not say this in the sense that human thought is subjected to the beckonings of others. Rather, he reasons with wisdom and carefully examines the passions of human nature. He almost digs up the diseases subtly hidden within the mind. He describes the body, to which an innate love of pleasure belongs, very skillfully putting upon himself the character of the one who still suffers from love of the body.
For although he himself is crucified to the world, as the world is to him (Gal 6:14), and is truly worthy of wonder, he wisely judges it necessary to consider not his own gift, but to set as the necessary foundation of the discourse the weakness of one who has not yet become like him.
Therefore when you hear, “For I do not understand what I do,” think of extremely sinful people who suppose that they are passing an excellent life, and that nothing can be set on a level with the luxury and vanity of this world. They feel disgust for the virtuous way of life, boast in their pleasures, and give themselves to them without restraint. Of them, I think, Paul says somewhere: “They think on earthly things; their god is the belly, and their glory is in their shame” (Phil 3:19).
Such people, since they perform a vicious deed as something very praiseworthy, can justly say: “For I do not understand what I do.” Therefore let them hear: “Wake up, drunkards, from your wine” (Joel 1:5). For as lovers of drink and those addicted to wine, having damaged the precision of thought because of this passion, cannot understand what they did in drunkenness, so those who suffer disturbance of thought from love of the flesh and shameful desires can never understand what they do.
Thus Paul explains to us the disease of the human heart when he says: “For I do not understand what I do.” And if there is someone whose heart is more receptive to the rebukes of conscience. And who is distressed that he sins, yet is still overcome by sinful pleasures and goes toward sin as though against his will, he will rightly say: “For I do not do what I will, but what I hate, that I do.”
How many, and how often, have admired continence, yet even after undertaking the practice of it have been overcome by the impulses of vile desire. Because their mind was dragged down toward what is worse, they committed sin and afterward were filled with despondency. It would be fitting for such people, and with full justification, since they have fallen into weakness almost against their will, to speak already in this way: “Now then it is no longer I who do it, but sin that dwells in me” (Rom 7:17).