Take a deep breath and get past the first paragraph. Our good saint is nothing if not thorough.
1 Now, this statement of ours, that it is within the power of free choice not to offer an impediment to grace, is applicable to those persons in whom natural potency is integrally present. But if, through a preceding disorder, one swerves toward evil, it will not at all be within his power to offer no impediment to grace. For, though at any definite instant he may be able to refrain from a particular act of sin by his own power, however, if long left to himself, he will fall into sin, whereby an impediment is offered to grace.
Indeed, whenever man’s mind swerves away from the state of rectitude it is evident that he has departed from the order of his proper end. So, what should be the most important thing in his affection, the ultimate end, becomes a less important object of love than that object to which his mind is inordinately turned, as if to an ultimate end. So, whenever anything comes up that is in agreement with the inordinate end but incompatible with his proper end, it will be chosen, unless he is brought back to his proper end, so that be favors the proper end above all things, and this is the effect of grace. However, in so far as he chooses something that is incompatible with his ultimate end, he offers an impediment to grace, for grace gives the direction to the end. It is consequently obvious that after sin a man cannot refrain from all sin during the period preceding his being brought back to the proper order by grace.
Notes A modern way to put all this may be to say that if you screw up and don’t care, you’ll go on screwing up until you do care, or are made to.
2 Besides, when the mind is inclined toward some object it does not stand in a relation of impartiality toward contrary alternatives, but, instead, is more favorable to the object to which it is inclined. But unless it be drawn away from it by a certain concern arising from rational examination, the mind chooses the object to which it is more favorable; hence, in sudden actions, an indication of one’s inner state of character may be especially found.
But it is not possible for a man’s mind continually to maintain such vigilance that it can make a rational investigation of whatever he ought to will or do. Thus, it follows that the mind at times chooses what it is inclined to, provided the inclination be undisturbed, And so, if it be inclined toward sin, it will not long stay without sinning, thus offering an impediment to grace, unless it is brought back to the state of rectitude.
Notes This is the price of habit. This is why Aristotle says to work your way into proper habits, “faking it until you make it.” That’s not a directtranslation.
3 The impulsion of the bodily passions also works toward this result, as also do the things that are attractive on the sense level, and most occasions for bad action whereby man is easily stimulated to sin, unless one be drawn back by means of a firm attachment to the ultimate end, which grace produces.
4 Consequently, the opinion of the Pelagians is evidently stupid, for they said that man in the state of sin is able to avoid sin, without grace. The contrary to this is apparent from the petition in the Psalm (70:9): “When my strength shall fail, do not forsake me.” And the Lord teaches us to pray: “And lead us not into temptation, but deliver us from evil.”
Notes Insults are not always improper.
5 However, although those who are in sin cannot avoid by their own power putting an impediment in the way of grace, as we showed, unless they be helped in advance by grace, nevertheless, this is regarded as their fault, because this defect is left in them as a result of a previous fault. Thus, for example, an intoxicated man is not excused from homicide committed in the state of intoxication which he got into through his own fault.
Notes Yes, even this attitude is changing, sadly enough. We are now guilty because of states are allowed to “come upon” us, unbidden. Great nonsense.
6 Besides, although he who is in sin does not have, of his own power, the ability entirely to avoid sin, he has it in his power at present to avoid this or that sin, as we said. Hence, whatever one he does commit, he does so voluntarily. And so, not undeservedly, he is held responsible for his fault.