He that obstinately denieth the truth before men upon earth, wilfully refuseth his soul's health in heaven.
Thomas AquinasThe Study of philosophy is not that we may know what men have thought, but what the truth of things is.
Thomas AquinasIt would seem that the ingratitude, whereby a subsequent sin causes the return of sins previously forgiven, is a special sin. For, the giving of thanks belongs to counter passion, which is a necessary condition of justice. But justice is a special virtue. Therefore this ingratitude is a special sin. Thanksgiving is a special virtue. But ingratitude is opposed to thanksgiving. Therefore ingratitude is a special sin.
Thomas Aquinas