It 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 AquinasHow can we live in harmony? First we need to know we are all madly in love with the same God.
Thomas AquinasWe can't have full knowledge all at once. We must start by believing; then afterwards we may be led on to master the evidence for ourselves.
Thomas Aquinas