In what sense efficacy depends on free choice
Thesis CXXXIV. The authors of this view hold that the efficacy of grace is something in the divine aid that comes before the will's working, and so does not hang on the will's consent and cooperation in the way Molina and his followers claim, as though it lay in a person's power to make grace efficacious or inefficacious. Even so, they do not deny that the efficacy of grace depends on free choice in some way. On their account it can be considered in two ways, in first act or in second act. Taken the first way, it is simply the power to bring about the effect, which is not distinct from the aid itself; in this respect it depends not on free choice but on God.
Taken the second way, efficacy means the actual working itself, the actual influence of grace on the supernatural work; and in this respect too it depends on God. Just as an instrument's influence on a work depends on the principal agent using it, so the influence of grace on a supernatural work depends on God as primary agent, who works through grace as through an instrument of his own. Yet this actual working of grace depends not only on God but also on free choice itself, as a partial cause without whose operation grace would not act. In this respect, then, that is, in second act, they say the efficacy of grace also depends on free choice. So Peter of Saint Joseph explains his mind on the matter in the treatise on divine grace, disputation 7, number 62.
Latin
CXXXIV. Caeterum quanquam authores illius sententiae efficaciam gratiae velint esse aliquid in auxilio divino, quod voluntatis operationem antecedit; ac proinde quod ab ejus consensu & cooperatione ea ratione non pendet, ut in hominis potestate situm sit gratiam vel efficacem, vel inefficacem reddere, ut volunt Molina, & qui eum sequuntur: nihilominus non negant gratiae efficaciam a libero arbitrio aliquo modo pendere. Etenim, juxta ipsos, efficacia gratiae duobus modis considerari potest, vel in actu primo, vel in actu secundo. Priori modo spectata ea nihil aliud est, quam vis efficiendi, quae non distinguitur ab ipso auxilio: & hac ratione efficacia gratiae non pendet a libero arbitrio, sed a Deo. Posteriori modo efficacia gratiae sumitur pro ipsa efficientia, seu influxu actuali gratiae in opus supernaturale. Et sub hac etiam consideratione efficacia gratiae pendet a Deo. Sicut enim influxus instrumenti in opus pendet ab agente principali, quod tali instrumento utitur: ita influxus gratiae in opus supernaturale pendet a Deo, ut ab agente primario, quod per gratiam, ut per instrumentum quoddam suum, operatur. Verum quia haec actualis efficientia gratiae, non tantum pendet a Deo, sed etiam ab ipso libero arbitrio, ut a causa partiali, sine cujus operatione gratia non ageret, ideo dicunt hoc respectu, id est, in actu secundo, gratiae efficaciam etiam a libero arbitrio pendere. Quemadmodum ea de re mentem suam explicat Petrus a Sancto Joseph in tractatu de gratia divina disput. 7. num. 62.