So the man moved acts by a necessity of infallibility yet keeps a real power not to act
On this teaching, then, a man whom God effectively moves to do this or that, or whom the dictate of his own judgment drives to it, does act necessarily, with a necessity of infallibility, while still keeping a real power not to act.
He is able not to act, yet he will surely act; and the absence of the act can never be found together with such a judgment or with such a motion from God.
Latin
XVIII. Igitur, juxta hanc doctrinam, homo ad hoc vel illud agendum efficaciter a Deo motus, vel judicii proprii dictamine impulsus, necessario quidem agit necessitate quadam infallibilitatis; sed simul tamen veram non agendi potestatem retinet. Et potest quidem non agere, sed certo tamen acturus est: neque contingere potest ut carentia actionis conjungatur unquam cum tali judicio, vel cum ejusmodi Dei motione.