Article — Prümmer, Manuale Theologiae Moralis
Article II. On the effects of venial sin
393. It has already been said above, n. 367, that it is very difficult to determine in what precisely the essence of venial sin is situated. But as to the effects which venial sin produces, the Doctors agree sufficiently. The principal effects are:
1. Privation of the actual brightness of the soul.
The soul in the state of sanctifying grace shines like a star. When venial sin comes upon it, this brightness is darkened, although it is not properly stained. St. Thomas deservedly does not admit that a stain properly so called comes from venial sin, as was said above in n. 391. Elsewhere,66 however, the Angelic Doctor admits a certain quasi-stain of venial sin, which brings with it "an inclination of affection disordered toward some temporal thing." The stain which is produced in the soul through mortal sin is not unfittingly compared to spiritual leprosy, which disfigures the face of a man and which cannot be removed unless the man's health has been restored, namely through a new infusion of sanctifying grace. But the quasi-stain caused by venial sin is filth adhering externally to the face, which can be washed away by the man himself, namely through the removal of disordered adherence to temporal things.
2. Difficulty in the exercise of charity and the other virtues.
St. Thomas constantly teaches that the infused habit of charity cannot be diminished, neither effectively nor meritoriously.67 Certainly charity can be destroyed through mortal sin, as was said above in n. 392; it can also be increased through meritorious works, but it cannot be diminished. Hence if someone having charity, for example of 100 degrees, commits a thousand venial sins, he will not obtain less glory in heaven than one who has equal charity without any venial sin. The first indeed will expiate punishments for the thousand venial sins committed through a long duration in purgatory, but when the washing has been completed he will have equal glory with the other. The reason why the habit of infused charity cannot be diminished is this: charity, as existing about the last end, that is, God himself, is not touched by venial sin, which is only a disorder about means to the end. For love of the end can exist whole, even if the means, not necessary, to the end are lightly esteemed. But although venial sin is not able directly to diminish charity, nevertheless it renders the acts of charity and of the other virtues more difficult, because little by little it causes evil passions and contrary habits.
3. Subtraction of many graces.
Venial sin leads to tepidity, and a tepid man is not so disposed to receive divine grace as a fervent man. A darkened crystal does not receive the rays of the sun so purely and abundantly as a transparent glass. Wherefore the words of Sacred Scripture,68 "Because thou art lukewarm, and neither cold nor hot, I will begin to vomit thee out of my mouth," can be applied to a soul given over to venial sins. God gradually withdraws grace from such a soul, and from this withdrawal the exercise of virtues becomes more burdensome, while a fall into mortal sin becomes more imminent. Hence as another effect of venial sin there is assigned:
4. Disposition toward mortal sin.
Although ten times a hundred thousand venial sins do not equal one mortal sin, yet venial sins often repeated, fully deliberate, proximately dispose to mortal sin. For, as is clear from what has been said, through venial sin the fervor of charity is diminished, disordered passion is increased, divine grace is gradually withdrawn, and as an almost inevitable consequence there is a fall into mortal sin. Hence it is said: "He that contemneth small things shall fall by little and little."69
5. Guilt of temporal punishment.
Since venial sin is a true fault, to it there is owed a punishment, which indeed is not eternal, but temporal or transitory. Many punishments of venial sin are indeed sometimes inflicted on this earth; but in the other life there is inflicted the punishment of purgatory, concerning which St. Thomas70 teaches with the other Doctors that the least punishment of purgatory exceeds the greatest punishment of this life. That purgatory really exists has been defined many times by the Church, for example by the Second Council of Lyons,71 by the Council of Florence,72 and by the Council of Trent.73
66 S. theol. 3, q. 87, a. 3 ad 3.
67 S. theol. 2, 2, q. 24, a. 10. Of the scholastics, almost Dionysius the Carthusian alone taught that venial sins directly diminish sanctifying grace and charity.
68 Apoc. 3, 16.
69 Eccli. 19, 1. Cf. S. theol. 1, 2, q. 88, a. 3.
70 4, dist. 21, q. 1, a. 1.
71 Denz. n. 464.
72 Denz. n. 693.