Rightly understood, the Reformed doctrine agrees in substance with the more received Thomists
From all this it is clear that the Reformed teaching on this point, correctly stated and understood as its own exponents intend it, does not in fact differ from the view of those in the Roman School called the more widely received Thomists.
These Thomists maintain that freedom is opposed not only to compulsion but also to natural necessity, necessity in the proper sense. Even so, they recognize that once everything required for acting is in place, the free creature's act follows necessarily, with a necessity of infallibility.
A free agent always keeps in itself the power not to act, even while it is actually acting, and all the more when it is on the point of acting. But once everything required on God's side and on the intellect's side for the will to act is in place, the will acts surely and infallibly, and its action cannot fail to follow. On their teaching, then, the power not to act or to act otherwise can perfectly well coexist with everything required for acting, but the absence of the act cannot, and still less a contrary act.
Latin
XXIX. Ex omnibus autem hisce manifestum est Reformatorum hac in parte doctrinam recte expositam atque intellectam, & ex mente eorum a quibus proponitur, reipsa non differre a sententia eorum qui in Schola Romana receptiores Thomistae appellantur. Quamvis enim contendant libertatem opponi non coactioni solum, sed necessitati quoque naturali & proprie dictae, nihilominus agnoscunt positis omnibus quae sunt ad agendum praerequisita, necessario sequi actum creaturae liberae necessitate quadam infallibilitatis. Quia licet agens liberum semper in se retineat potestatem non agendi, etiam quum reipsa agit, & a fortiori quum est in proximo ad agendum; positis tamen omnibus quae, tum ex parte Dei, tum ex parte intellectus praerequiruntur ut voluntas agat, agit illa certo & infallibiliter, & impossibile est actionem ejus non sequi. Nempe ex eorum doctrina, cum omnibus illis quae sunt ad agendum praerequisita optime conjungi & consistere potest potentia non agendi, aut aliter agendi, non tamen carentia actus, & multo minus actus contrarius.