Freedom kept: the practical judgment could have been otherwise
Thesis XXXIX. Yet they do not think that this efficacy of grace removes or lessens the freedom of the human will in any respect, or that a person's good actions, which depend on that grace as their cause, are any less free for it. For through his grace God does not merely cause us to do good works in keeping with his will; he also causes us to do them in the way that suits human nature, and therefore freely.
That efficacious motion of divine grace brings it about in us that we choose the good on the basis of a prior judgment of the practical intellect, and in such a way that, on a different judgment of the same intellect, we could choose evil; and this is enough for freedom in the full sense. Although grace surely and infallibly ensures that our will is carried toward this or that good, with the mind's practical judgment going before, it does not prevent the intellect, while following that guidance, from keeping the power to judge otherwise, nor the will from keeping the power to choose otherwise; and freedom consists in this. A person is wholly free who of himself is so indifferent to acting or not acting that while he acts he has the power not to act or to act otherwise.
Latin
XXXIX. Nec tamen putant per istam gratiae efficaciam voluntatis humanae libertatem ulla ex parte, vel tolli vel minui; & propterea minus esse liberas bonas hominis operationes, quae a gratia ista ut a causa sua pendent. Idque quia Deus per gratiam suam, non simpliciter facit ut faciamus opera bona, & ejus voluntati conformia, verum etiam facit ut ea faciamus, secundum modum humanae naturae convenientem, adeoque libere. Siquidem efficax illa gratiae divinae motio id praestat in nobis, ut ex praevio judicio intellectus practici bonum eligamus, & quidem ita, ut ex diverso ejusdem intellectus judicio possemus malum eligere: quod ad plenam rationem libertatis sufficit. Nam quamvis gratia certo & infallibiliter praestet, ut in bonum hoc aut illud voluntate nostra feramur, praevio mentis practicae judicio: non tamen obstat quominus intellectus ejus ductum sequens retineat potestatem aliter judicandi, & voluntas potestatem aliter eligendi, qua in re ratio libertatis sita est. Nempe omnino liber est, qui ex se ad agendum, aut non agendum ita indifferens est, ut dum agit potestatem habeat non agendi, aut aliter agendi.