Summa Theologiae Moralis, vol. I: De Principiis

S. Th. II-II, q. 37-42.

954. Sins against private peace. — To peace which is an effect of charity several sins are opposed. To private peace is opposed:

1) In the heart discord, which is directly contrary to concord or the union of wills, and is a dissension of wills (not only of intellects) concerning the good of God or of neighbor which we ought to will out of charity, namely about the good necessary to which we are bound to consent.

Discord happens in two ways: a) per se when one knowingly and intentionally dissents from the good of God or of neighbor to which he ought to consent, and thus it is a mortal sin of its genus because it is contrary to charity; b) per accidens when the intention of some is toward the good that pertains to the honor of God or the utility of neighbor, but one judges this to be good, another however has the contrary opinion, and such discord which is rather of opinions and intellects than of wills, is not against charity nor sin, unless there is error concerning those things which are of necessity for salvation, or the limits of moderation are exceeded so that undue pertinacity is employed. — Discord arises from vainglory, because we want our own and our own opinion more than is right.

2) From discord is often born contention, which is an altercation of words by which one contradicts another inordinately, whether by impugning the truth, or by defending it in an undue way e.g. with too much acrimony. In the first case it is a mortal sin of its genus, namely in matter of great moment: of faith, of morals, of justice, etc.; in the second case it is only venial, unless it generates grave scandal. It also arises from vainglory by which each of the contending tries to gain victory over the other.

3) From discord and contention is sometimes born quarrel, which is a fight of hands between private persons by which, with angry minds, one tries to strike or harm another. It is a mortal sin of its genus in the aggressor; if however it does not exceed the measure, as a slight fight, it is venial. In the one defending himself it is not sin, if he does not exceed the limits of moderation; if he exceeds a little, it is venial; if much, mortal, e.g. if without necessity someone rises up to gravely harm another. — It arises from anger.

955. Sins against public peace. — 1) To the peace of the Church, schism which is the voluntary separation of oneself from the unity of the Church, while retaining the profession of faith, or the voluntary separation of a baptized person from the Catholic Church. It is committed in two ways, for "the unity of the Church is attended in two things, namely a) in the connection of the members of the Church to one another..., and b) again in the order of all the members to one head... And therefore schismatics are called 1) (perfectly) those who refuse to be subject to the supreme Pontiff (with rebellion, so that they pertinaciously refuse to obey the precepts), and 2) those who refuse to communicate with members of the Church subject to him" (in doctrine, worship, sacraments); from which it is clear that it is a most grave sin and mortal of its whole genus. It is however less grave than infidelity, which is against God himself inasmuch as he is in himself the first truth on which faith rests, whereas schism is against the unity of the Church, which is a participated good and less than God himself. And although charity is nobler than faith, the sin which is opposed against the secondary good of charity, namely the good of neighbor, is less than infidelity, because the good of neighbor is less than the object of faith which is God himself.

2) To the peace of the civil multitude, both a) unlawful war; and b) sedition, which is a tumultuousness or aggressive war by which one part of the state unjustly rises up against another or against the legitimate prince, which latter case is called rebellion. It is a sin all the graver as the common good (namely peace and unity of society) surpasses the private good; whence it is mortal of its whole genus.

These sins are also against justice, and are better considered in tr. on Justice.

956. Remark. — External heretics are also schismatics, but not conversely, although however schism leads to heresy. Schismatics also are punished with the same ecclesiastical penalties as heretics; moreover about communication with schismatics and about co-operation toward schism the same is to be said as for heresy (cfr. tr. on Faith).