2030[Sent. super Cap. 8]Again, whoever says that God does not will all men to be saved, but only the certain number of the predestined, is saying a harsher thing than ought to be said of the inscrutable depth of the grace of God, who both wills that all should be saved and come to a knowledge of the truth (1 Tim. 2:4), and fulfills the proposal of His will in those whom, when He foreknew them, He predestined, when He predestined them, He called, when He called them, He justified, and, when He justified them, He glorified (Rom. 8:30). . . . And thus, those who are saved are saved because God willed them to be saved, and those who perish do perish because they deserved to perish.
William A. Jurgens, The Faith of the Early Fathers, 3:190.
Primary source [click here for more]:
"QUALIFICATION OF ARTICLE 8: Likewise, he who says that God will not have all men to be saved but only the fixed number of the predestined, speaks more harshly than we should speak of the depth of the unsearchable grace of God.God, who will have all men to be saved and to come to the knowledge of the truth fulfills this free decree of His in those whom He foreknew and predestined, predestined and called, called and justified, justified and glorified. In so doing, He does not lose anyone that belongs to that fulness of the nations and to that completeness of the race of Israel for whom the eternal kingdom was prepared in Christ before the creation of the world. Out of the entire world the whole world of the elect is chosen; out of the totality of men the totality of the elect are adapted. Nor can the unbelief and disobedience of many annul the promise God made to Abraham: In thy seed shall all the nations of the earth be blessed.”Whatsoever God has promised, He is able to perform.’” And so the elect are saved because God willed them to be saved, and the reprobate are lost because they deserve to be lost."
Prosper of Aquitaine: Defense of St. Augustine, trans. P. De letter (New York: Newman Press, 1963), 159.