In this short excerpt from his massive and unfinished systematic treatise, Summa Theologica, Aquinas discusses the difficult doctrine of reprobation 1
Whether God reprobates any man?
Objection 1: It seems that God reprobates no man. For nobody reprobates what he loves. But God loves every man, according to (Wis. 11:25): “Thou lovest all things that are, and Thou hatest none of the things Thou hast made.” Therefore God reprobates no man.
Objection 2: Further, if God reprobates any man, it would be necessary for reprobation to have the same relation to the reprobates as predestination has to the predestined. But predestination is the cause of the salvation of the predestined. Therefore reprobation will likewise be the cause of the loss of the reprobate. But this false. For it is said (Osee 13:9): “Destruction is thy own, O Israel; Thy help is only in Me.” God does not, then, reprobate any man.
Objection 3: Further, to no one ought anything be imputed which he cannot avoid. But if God reprobates anyone, that one must perish. For it is said (Eccles. 7:14): “Consider the works of God, that no man can correct whom He hath despised.” Therefore it could not be imputed to any man, were he to perish. But this is false. Therefore God does not reprobate anyone.