On the Freedom of the Will, With an Explanation and Interpretation of Those Statements of Scripture Which Appear to Nullify It
13 It is not without reason, then, that he who is abandoned, is abandoned to the divine judgment, and that God is long-suffering with certain sinners; but because it will be for their advantage, with respect to the immortality of the soul and the unending world, that they be not quickly brought into a state of salvation, but be conducted to it more slowly, after having experienced many evils. For as physicians, who are able to cure a man quickly, when they suspect that a hidden poison exists in the body, do the reverse of healing, making this more certain through their very desire to heal, deeming it better for a considerable time to retain the patient under inflammation and sickness, in order that he may recover his health more surely, than to appear to produce a rapid recovery, and afterwards to cause a relapse, and (thus) that hasty cure last only for a time; in the same way, God also, who knows the secret things of the heart, and foresees future events, in His long-suffering, permits (certain events to occur), and by means of those things which happen from without extracts the secret evil, in order to cleanse him who through carelessness has received the seeds of sin, that having vomited them forth when they came to the surface, although he may have been deeply involved in evils, he may afterwards obtain healing after his wickedness, and be renewed. For God governs souls not with reference, let me say, to the fifty years of the present life, but with reference to an illimitable age: for He made the thinking principle immortal in its nature, and kindred to Himself; and the rational soul is not, as in this life, excluded from cure.
14. Come now, and let us use the following image from the Gospel. There is a certain rock, with a little surface-soil, on which, if seeds fall, they quickly spring up; but when sprung up, as not having root, they are burned and withered when the sun has arisen. Now this rock is a human soul, hardened on account of its negligence, and converted to stone because of its wickedness; for no one receives from God a heart created of stone, but it becomes such in consequence of wickedness. If one, then, were to find fault with the husbandman for not sowing his seed sooner upon the rocky soil, when he saw other rocky ground which had received seed flourishing, the husbandman would reply, “I shall sow this ground more slowly, casting in seeds that will be able to retain their hold, this slower method being better for the ground, and more secure than that which receives the seed in a more rapid manner, and more upon the surface.” (The person finding fault) would yield his assent to the husbandman, as one who spoke with sound reason, and who acted with skill: so also the great Husbandman of all nature postpones that benefit which might be deemed premature, that it may not prove superficial. But it is probable that here some one may object to us with reference to this: “Why do some of the seeds fall upon the earth that has superficial soil, the soul being, as it were, a rock?” Now we must say, in answer to this, that it was better for this soul, which desired better things precipitately, and not by a way which led to them, to obtain its desire, in order that, condemning itself on this account, it may, after a long time, endure to receive the husbandry which is according to nature. For souls are, as one may say, innumerable; and their habits are innumerable, and their movements, and their purposes, and their assaults, and their efforts, of which there is only one admirable administrator, who knows both the season, and the fitting helps, and the avenues, and the ways, viz., the God and Father of all things, who knows how He conducts even Pharaoh by so great events, and by drowning in the sea, with which latter occurrence His superintendence of Pharaoh does not cease. For he was not annihilated when drowned: “For in the hand of God are both we and our words; all wisdom also, and knowledge of workmanship.” And such is a moderate defence with regard to the statement that “Pharaoh's heart was hardened,” and that “God has mercy upon whom He will have mercy, and whom He will He hardens.”
15. Let us look also at the declaration in Ezekiel, which says, “I shall take away their stony hearts, and will put in them hearts of flesh, that they may walk in My statutes and keep My precepts.” For if God, when He wills, takes away the stony hearts, and implants hearts of flesh, so that His precepts are obeyed and His commandments are observed, it is not in our power to put away wickedness. For the taking away of the stony hearts is nothing else than the taking away of the wickedness, according to which one is hardened, from him from whom God wills to take it; and the implanting of a heart of flesh, so that a man may walk in the precepts of God and keep His commandments, what else is it than to become somewhat yielding and unresistent to the truth, and to be capable of practising virtues? And if God promises to do this, and if, before He takes away the stony hearts, we do not lay them aside, it is manifest that it does not depend upon ourselves to put away wickedness; and if it is not we who do anything towards the production within us of the heart of flesh, but if it is God's doing, it will not be our own act to live agreeably to virtue, but altogether (the result of) divine grace. Such will be the statements of him who, from the mere words (of Scripture), annihilates free-will. But we shall answer, saying, that we ought to understand these passages thus: That as a man, e.g., who happened to be ignorant and uneducated, on perceiving his own defects, either in consequence of an exhortation from his teacher, or in some other way, should spontaneously give himself up to him whom he considers able to introduce him to education and virtue; and, on his yielding himself up, his instructor promises that he will take away his ignorance, and implant instruction, not as if it contributed nothing to his training, and to the avoiding of ignorance, that he brought himself to be healed, but because the instructor promised to improve him who desired improvement; so, in the same way, the Word of God promises to take away wickedness, which it calls a stony heart, from those who come to it, not if they are unwilling, but (only) if they submit themselves to the Physician of the sick, as in the Gospels the sick are found coming to the Saviour, and asking to obtain healing, and so are cured. And, let me say, the recovery of sight by the blind is, so far as their request goes, the act of those who believe that they are capable of being healed; but as respects the restoration of sight, it is the work of our Saviour. Thus, then, does the Word of God promise to implant knowledge in those who come to it, by taking away the stony and hard heart, which is wickedness, in order that one may walk in the divine commandments, and keep the divine injunctions.
Source: De Principiis (New Advent)