Chapter — Wouters, Manual of Moral Theology
Chapter I. On Internal Sins
Internal sins - besides omission of an internal act by reason of the precept of charity itself - are hatred and envy.
I. What hatred is and into how many kinds it is distinguished, see n. 520. But the morality of hatred toward one's neighbor is outlined in these points:
Hatred of abomination of the person is a grave sin, since it excludes one's neighbor from common charity. Hatred of abomination of a quality is good, evil, or (at least from the object) indifferent, according as the quality which someone turns away from is good or evil or indifferent (St. Alphonsus, II, 30; cf. St. Thomas, II-II, q. 34, a. 3).
Hatred of enmity is a sin grave from its genus, that is, grave or light according as it regards a grave or light evil, or deprivation of a grave or light good (St. Alphonsus, II, 30).
From hatred of enmity must be distinguished the act by which someone in an ordered way wishes evil to his neighbor; namely insofar as it yields to the good of the one wishing, or of the neighbor, or of a third party, or of the community. Hence it is lawful, for example, to desire temporal evil for one's neighbor, so that he may be amended from sins; likewise the penalty of a delict, insofar as it restores the violated order and turns the delinquent and others away from transgressions; likewise "to wish death for a heresiarch or a disturber of public peace, on account of the common good, and of many; according to that saying in Galatians 5:12: Would that... they be cut off. Likewise, to be saddened over the fact that dignities are conferred on the unworthy; or over the health of him who from it takes an occasion of sinning" (St. Alphonsus, II, 30; St. Thomas, II-II, q. 108, a. 1). Yet it is required that the evil of one's neighbor deservedly be postponed to the good that will follow. Hence there were condemned by Innocent XI, proposition 13: "If you do it with due moderation, you can, without mortal sin, be saddened over the life of someone, and rejoice over his natural death, and seek and desire it by an inefficacious affection: not indeed from displeasure with the person, but on account of some temporal advantage";1 likewise proposition 14: "It is lawful by an absolute desire to wish the death of one's father; not indeed as the evil of the father, but as the good of the one wishing, because, namely, a rich inheritance will come to him";2 likewise proposition 15: "It is lawful for a son to rejoice over the parricide of a parent, perpetrated by himself in drunkenness, on account of the immense riches obtained from the inheritance."3
Note 1. It is probable that "in confession it is enough if you say that you wished grave evil for your neighbor; nor is there need to explain the species of evil, for example death, infamy, etc., because all are comprehended under one aspect of evil" (St. Alphonsus, II, 30). The opposite must be said of a purpose of inflicting diverse evils (St. Alphonsus, loc. cit., n. 297).
Note 2. Penitents rather often confuse illicit hatred with hatred of abomination of a quality, or even hatred with a certain natural and involuntary antipathy.
1 Denzinger-Bannwart, n. 1163.
2 Denzinger-Bannwart, n. 1164.
3 Denzinger-Bannwart, n. 1165.