Cap. VIII Arg. 5 Resp.: Rom. 9 explains failure to attain justice, not eternal reprobation; Estius
To the first witness from Romans 9: Paul is not giving the reason why the Jews were reprobated, but why they failed to attain true righteousness before God — however keen they seemed as pursuers of righteousness. That happened, he says, because they sought righteousness in their works and exact law-keeping, despising justification by faith; justification from works of the law is plainly impossible for a man weakened and corrupted by sin, and every sinner must flee to faith to be justified before God. Not only our theologians follow this reading, but among the Romanists William Estius of Douai expressly does so on this very place: Know that here no reason is given why the Jews were reprobated, but why they did not attain righteousness. So this first testimony is plainly off the point.
Latin
Ad primum testimonium ex nono ad Romanos petitum respondeo, Non reddi rationem cur reprobati fuerint Judaei, sed cur justitiam veram coram Deo minime sunt assecuti, utcunque videantur fuisse justitiae acerrimi sectatores. Id autem inde evenisse dicit Apostolus, quod justitiam quaerebant in operibus suis, et exacta legis observatione, spreta justificatione per fidem; cum ex operibus legis justificari sit homini per peccatum infirmato et corrupto plane impossibile, et necesse sit omni peccatori ad fidem confugere, ut coram Deo justificetur. Hanc interpretationem non modo Theologi nostri, sed etiam ex Pontificiis Gulielmus Estius Professor Duacenus expresse sequitur in Commentariis suis ad hunc ipsum locum, ubi inter alia et haec verba posuit, Scito non hic reddi rationem cur reprobati fuerint Judaei, sed cur non justitiam assecuti. Prius igitur hoc testimonium a proposito plane alienum.