§ I. On Mortal Sin

I. Existence of mortal sins. There are mortal¹ or grave sins. This is of faith from these words of the Council of Trent: "If anyone shall say that there is no mortal sin except unbelief, or that grace once received is lost by no other sin, however grave and enormous, except the sin of unbelief, let him be anathema."² The same Council teaches that "all mortal sins must be recounted by penitents."³ It is proved: 1. from Sacred Scripture, which very often declares that there are sins because of which men are deprived of divine friendship and are damned eternally. Thus, for example, "The impious man and his impiety are hateful to God";⁴ likewise, "Depart from me, you cursed, into eternal fire."⁵ It is proved: 2. from the holy Fathers. Thus St. Jerome: "There are light sins, there are grave ones";⁶ St. Augustine: "For who would say that one must sin, even if one sin is damnable, another venial?";⁷ likewise St. Basil,⁸ St. John Chrysostom,⁹ St. Ambrose.¹⁰ It is proved: 3. from reason, because there are sins which plainly turn one away from the ultimate end, as we shall soon explain more fully.

¹ It is called mortal because it takes away the principle of spiritual life, namely habitual grace, and brings death to the soul (St. Alphonsus, V, 51; St. Thomas, I-II, q. 72, a. 5).

² Session 6, canon 27.

³ Session 14, chapter 5.

⁴ Wis. 14:9.

⁵ Matt. 25:41.

⁶ Bk. 2, Against Jovinian, n. 30.

⁷ Contra mendacium, c. 8, n. 19.

⁸ Homily on Psalm 7, v. 3, n. 2.

⁹ Homily 12 on the Epistle to the Romans, n. 18.

¹⁰ Bk. 2, De poenitentia, c. 18, n. 95.

II. Nature of mortal sin. Every sin is a certain disorder from the ultimate end, i.e., from God, or a certain deformity from the rule, i.e., from the law directing man to the ultimate end. Now mortal sin is disorder in every way, or aversion from the ultimate end. Therefore such a sin utterly overturns the due order to the ultimate end; hence it is said to be against the substance of the due order. "When the soul," says St. Thomas, "is disordered by sin even to aversion from the ultimate end, namely God, to whom it is united by charity, then it is mortal sin" (I-II, q. 72, a. 5; St. Alphonsus, V, 11). Now aversion from the ultimate end, which is contained in mortal sin, takes place through conversion toward a creature as toward the ultimate end.

Corollary. Mortal sin is of infinite malice, because by placing a creature before the infinite God it inflicts an infinite injury upon God. "Whoever," says St. Thomas, "places something less worthy before something more worthy, does injury to it, and so much the more as the thing is more worthy. But whoever establishes for himself an end in a temporal thing, which everyone sinning mortally does, by this very fact, as to his affection, places the creature before the Creator, loving the creature more than the Creator" (De veritate, q. 28, a. 2).

III. Division of mortal sin. Mortal sins are divided into mortal sins from their genus, mortal sins from their whole genus, and mortal sins by accident. Now:

1. Those are usually called mortal from their genus¹ which according to their proper matter can be grave, and in fact are grave or light according as the matter is grave or light.

2. Mortal sins from their whole genus are those whose matter is always grave, so that they cannot be light except from ignorance of the grave malice, or from imperfection of the act. Such are, for example, unbelief, despair, blasphemy, perjury, etc.

3. There will be discussion of mortal sins by accident in the scholion.

¹ According to St. Thomas, mortal from its genus seems to be that which, if it is present according to its perfect notion, is always grave. This seems to be deduced from these words of the holy Doctor: "It must be said that one who does injustice in small things falls short of the perfect notion of doing what is unjust, insofar as it can be held not to be altogether against the will of the one who suffers this; for example, if someone takes one apple from another, or something of that sort, concerning which it is probable that the other is not injured by it and that it does not displease him" (II-II, q. 59, a. 4, ad 2; II-II, q. 66, a. 6, ad 3).

IV. Conditions of mortal sin. For mortal sin there are required: 1. grave matter; 2. the legislator's intention of obliging under grave obligation; 3. full advertence; 4. full or perfect consent. The reason for the first and second has been explained in n. 149. The reason for the third and fourth is that, in order that man simply turn himself away from the ultimate end and merit eternal punishment, a perfect human act is required (St. Alphonsus, V).

1. What grave matter is, see n. 149 and the things to be said under VI.

2. Whence the legislator's intention of obliging under grave obligation is discerned, see n. 149. This intention, with regard to divine law, whether natural or positive, is always present if the matter is grave. With regard to human laws in grave matter, it is presumed to be present unless the contrary is established (n. 149).

3. Full advertence, and actual advertence, either in the act itself or when its cause was placed. Now full advertence is had when someone, fully self-possessed or with mind free, adverts to the grave malice. It suffices, however, that he advert to it confusedly (St. Alphonsus, V, 3).

4. Full consent is that which follows full advertence.

V. Effects of mortal sin. Mortal sin: 1. deprives one of sanctifying grace and charity, and of the other supernatural virtues except faith and hope, and finally of the gifts of the Holy Spirit. 2. It renders dead the good works done while sin has not yet been remitted, i.e., worthy of no heavenly reward; likewise it renders works done previously mortified, so that they are to be deprived of heavenly reward unless they revive through repentance. 3. It deprives the sinner of the special providence by which God rules his friends; deprived of this, the sinner, unless he soon comes to his senses, will soon slip into other sins. 4. It often induces temporal evils, both public and private. 5. It induces liability to punishment, concerning which there was discussion in n. 267.

VI. Criteria for discerning mortal sins. Mortal sins are discerned, as was said concerning discerning the grave obligation of law (n. 149): 1. from Sacred Scripture; 2. from definitions of the Church; 3. from the consensus of the holy Fathers; 4. from the consensus of theologians; 5. from the gravity of the terms by which some sin is prohibited; 6. from the gravity of the punishment; 7. finally, from the intrinsic reason, insofar as it demonstrates that some sin is opposed to charity. Concerning this, observe: since mortal sin consists in aversion from the ultimate end (n. 278), but conversion toward the ultimate end takes place through charity, therefore those sins are mortal which are simply opposed to charity. Now these are simply opposed to charity: 1. those which are opposed to charity contrarily, such as sins of hatred against God, society, or neighbor; 2. those which inflict grave injury, whether upon God himself, as unbelief and despair; or upon the good of God, i.e., his honor, as the explicit choice of a creature for the ultimate end, idolatry, simony, etc.; or upon the good of the species, as lust; or upon one's own good, as suicide; or upon the good of neighbor and society, as grave theft (cf. St. Thomas, I-II, q. 88, a. 2; II-II, q. 59, a. 4; II-II, q. 66, a. 6). But for judging whether something is gravely opposed to the good of God, of society, of oneself, or of one's neighbor, not only competent authority must be attended to, but also, if authority does not settle the matter, common estimation.