(b) mortal sin is also committed when injury is done to a public right in a matter so important that the community is with good reason gravely averse to the commission of the injury. This happens when the common good is directly attacked, as when a citizen rebels against lawful government, or when the peace and security of the community is imperilled because of injury done to a private person, as when one steals a sum that is considerable from a wealthy person, even though the latter will not seriously feel the loss. Hence, an injury to a private person that does not seriously harm him may seriously harm the community, and be gravely sinful on account of the disastrous consequences to social order that would follow if such an injury were not gravely forbidden.
1723. Moral Species of Legal and of Particular Injustice.—These are distinguished according to the main classes of objects or rights that are injured or offended (see 199). Hence, there are the following four kinds of injustice:
(a) injuries to spiritual rights or goods, whether natural or supernatural (e.g., superstition, idolatry, simony);
(b) injuries to internal goods of soul (e.g., lies) or of body (e.g., murder, mutilation);
(c) injuries to external goods, whether incorporeal (e.g., calumny) or corporeal (e.g., theft, fraud).
1724. Accidental Forms of Injustice.—There are also many accidental forms of injustice, that is, variations that do not of themselves change the moral species (see 200).
(a) Thus, as to its manner, injustice is done either positively, by action (e.g., by stealing from an employer), or negatively, by omission (e.g., by allowing another to steal from one’s employer). In both cases the same kind of injustice is committed; for example, he who permits theft is just as much a thief as if he had stolen himself.
(b) As to its consequences for the injured person, injustice is either merely injurious or injurious and damaging, according as a strict right is violated without loss (e.g., adultery from which no child is born), or with loss to the injured party (e.g., adultery from which a child is born). The character of the sin is the same in both cases, but in the latter case restitution is due (cfr. 1199, 1200). The loss (_damnum_) that results from violation of a strict right (_injuria_) may be in internal goods (such as salvation, life, health, sanity of mind) or in external goods (such as reputation, money, property).
(c) As to its consequences for the party who does the injury, injustice is either profitable to him (as in the case of unjust taking) or unprofitable (as in the case of unjust damage). The moral species is the same in either case, for the fact that the unjust person gains by his injustice does not make the injury greater, and the fact that he does not gain does not make the injury less.
1725. Injury is not suffered by one who knows and wills an act that is done contrary to his right (Rule 27 of the Decretals), for such a one cedes his right. Hence, if a man looks out with a smile while neighborhood boys take apples from his orchard and the latter take this as permission, no injustice, material or formal, is done. But the legal maxim needs interpretation, for the following two conditions are necessary in order that there be a surrender of right: