Rivet's account of free choice is taken word for word from Alvarez
That the view of this Diego Alvarez, and of the others called with him the more recent Thomists, is here exactly the same as that of the teachers of the Reformed Church is well attested by the very learned Andrew Rivet, some years ago professor at the University of Leiden. When he set out his own mind on the freedom of human choice, he used no words but those taken from Alvarez himself, in his Summa of controversies, treatise 4, question 3.
He grants that one may accept the definition of free choice as 'a faculty of the will by which, given everything required beforehand for acting, it can act or not act', provided this is taken in the divided sense, not the composite. 'That is,' he says, 'if someone says that, given everything required beforehand for the act in the order of reason or of time, free choice can act or not act, meaning that together with those same prerequisites there is in free choice the ability and power by which it could act or not act if it wished, as Diego Alvarez distinguishes. For even God's effective motion, by which the will is determined to such an act, does not take from free choice the ability to perform that act or the contrary one; it only brings it about that, while free choice is able to perform such an act or not, it performs it infallibly and yet freely. When it does so, the power to another act remains, because it is not determined by nature to such acts.
For, as the same author says, in a contingent and free cause there is at once a power to either of two opposites, but not a power to have the opposites at once. A power to one act does not conflict with a power to the contrary act, nor even with the contrary act itself, though contrary acts do conflict with each other in the same subject. Hence created free choice, not only before it is determined to one act but in the very instant in which God determines it and it determines itself to that act, has at the same moment a power by which it can produce the contrary act if it wishes. It has no power to have the contrary act at the same moment, because two contrary acts cannot be in the same power at once, only one after the other.'
All these words are either quoted outright or at least borrowed from Diego Alvarez. So is what Rivet adds as that teacher's conclusion, which he endorses: that it does not belong to the nature or definition of free choice that, given everything required beforehand in the order of causality for performing such an act, it can leave that same act undone in the composite sense, if the composition is made between those prerequisites and the absence of the act or a contrary act. In other words, with God's effective help it cannot at the same time be true that free choice does not produce the act of love, or that it produces an act contrary to the love of God.
Latin
XXXI. Ac profecto eandem plane hic esse sententiam Didaci istius Alvares, & aliorum qui cum eo recentiores Thomistae nuncupantur, cum sententia Doctorum Ecclesiae Reformatae, testis idoneus est Vir Doctissimus Andreas Rivetus ante annos aliquot in Academia Leydensi Professor, dum non aliis verbis quam quae sunt ex ipso Alvarez desumpta, mentem suam de arbitrii humani libertate exprimere voluit. In summa controversiarum tract. 4. quaest. 3. Fatetur enim tolerari posse definitionem liberi arbitrii per quam dicitur facultas voluntatis qua, positis omnibus ad agendum praerequisitis, possit agere, aut non agere, dummodo id intelligatur non in sensu composito, sed in sensu diviso, Nempe, inquit, si quis dicat positis omnibus antecedenter requisitis, secundum ordinem rationis, vel temporis ad actum, liberum arbitrium posse operari, vel non operari, ita videlicet, ut cum eisdem praerequisitis stet simul in libero arbitrio facultas & potentia, qua possit operari, vel non operari si vellet, ut distinguit Didacus Alvares, quia etiam motio Dei efficax qua ad talem actum voluntas determinatur, non tollit a libero arbitrio facultatem operandi illum actum vel operandi actum contrarium, sed solum efficit, quod cum liberum arbitrium possit operari vel non operari talem actum infallibiliter, libere tamen operetur illum. Quod cum facit, manet potentia ad alium, quia ad tales actus non est naturaliter determinata. Nam ut ait idem, in causa contingenti & libera, simul est potentia ad utrumque oppositum, non tamen est potentia ad opposita simul habenda, quia potentia ad actum unum, non repugnat potentiae ad actum contrarium, nec etiam repugnat actui contrario, actus autem contrarii repugnant inter se in eodem subjecto; unde liberum arbitrium creatum non solum antequam determinetur ad unum actum, sed etiam in ipso instanti, in quo determinatur a Deo, & seipsum determinat ad eundem actum, simul habet potentiam qua potest actum contrarium producere si velit, non tamen ad actum contrarium simul habendum, quia duo actus contrarii simul in eadem potentia esse non possunt, sed successive. Quae omnia verba ex Didaco Alvarez vel expresse citata, vel saltem mutuata sunt, ut & illud quod subjungit tanquam ejusdem doctoris conclusionem quae ipsi probatur, nempe, non esse de ratione liberi arbitrii aut definitione ejus, quod positis omnibus secundum ordinem causalitatis antecedenter praerequisitis ad operandum talem actum, possit eundem actum non operari in sensu composito, si compositio fiat inter hujusmodi praerequisita, & carentiam talis actus, seu actum contrarium, id est, cum auxilio Dei efficaci, non simul stare quod liberum arbitrium non producat actum dilectionis, aut eliciat actum dilectioni Dei contrarium.