Whether hatred of one's neighbor is always a sin?
Objection 1: It would seem that hatred of one's neighbor is not always a sin. For no sin is commanded or counselled by God, according to Prov. 8:8: "All My words are just, there is nothing wicked nor perverse in them." Now, it is written (Lk. 14:26): "If any man come to Me, and hate not his father and mother . . . he cannot be My disciple." Therefore hatred of one's neighbor is not always a sin.
Objection 2: Further, nothing wherein we imitate God can be a sin. But it is in imitation of God that we hate certain people: for it is written (Rom. 1:30): "Detractors, hateful to God." Therefore it is possible to hate certain people without committing a sin.
Objection 3: Further, nothing that is natural is a sin, for sin is a "wandering away from what is according to nature," according to Damascene (De Fide Orth. ii, 4,30; iv, 20). Now it is natural to a thing to hate whatever is contrary to it, and to aim at its undoing. Therefore it seems that it is not a sin to hate one's I enemy.
On the contrary, It is written (1 Jn. 2:9): "He that . . . hateth his brother, is in darkness." Now spiritual darkness is sin. Therefore there cannot be hatred of one's neighbor without sin.
I answer that, Hatred is opposed to love, as stated above (FS, Q 29, A 2); so that hatred of a thing is evil according as the love of that thing is good. Now love is due to our neighbor in respect of what he holds from God, i.e. in respect of nature and grace, but not in respect of what he has of himself and from the devil, i.e. in respect of sin and lack of justice.
Consequently it is lawful to hate the sin in one's brother, and whatever pertains to the defect of Divine justice, but we cannot hate our brother's nature and grace without sin. Now it is part of our love for our brother that we hate the fault and the lack of good in him, since desire for another's good is equivalent to hatred of his evil. Consequently the hatred of one's brother, if we consider it simply, is always sinful.
Reply to Objection 1: By the commandment of God (Ex. 20:12) we must honor our parents---as united to us in nature and kinship. But we must hate them in so far as they prove an obstacle to our attaining the perfection of Divine justice.
Reply to Objection 2: God hates the sin which is in the detractor, not his nature: so that we can hate detractors without committing a sin.
Reply to Objection 3: Men are not opposed to us in respect of the goods which they have received from God: wherefore, in this respect, we should love them. But they are opposed to us, in so far as they show hostility towards us, and this is sinful in them. In this respect we should hate them, for we should hate in them the fact that they are hostile to us.
II–II · Q. 34, Art. 4: Whether hatred of our neighbor is the most grievous sin against our neighbor?
Whether hatred of our neighbor is the most grievous sin against our neighbor?
Objection 1: It would seem that hatred of our neighbor is the most grievous sin against our neighbor. For it is written (1 Jn. 3:15): "Whosoever hateth his brother is a murderer." Now murder is the most grievous of sins against our neighbor. Therefore hatred is also.
Objection 2: Further, worst is opposed to best. Now the best thing we give our neighbor is love, since all other things are referable to love. Therefore hatred is the worst.
On the contrary, A thing is said to be evil, because it hurts, as Augustine observes (Enchiridion xii). Now there are sins by which a man hurts his neighbor more than by hatred, e.g. theft, murder and adultery. Therefore hatred is not the most grievous sin.
Moreover, Chrysostom [*Hom. x in the Opus Imperfectum, falsely ascribed to St. John Chrysostom] commenting on Mat. 5:19, "He that shall break one of these least commandments," says: "The commandments of Moses, Thou shalt not kill, Thou shalt not commit adultery, count for little in their reward, but they count for much if they be disobeyed. On the other hand the commandments of Christ such as, Thou shalt not be angry, Thou shalt not desire, are reckoned great in their reward, but little in the transgression." Now hatred is an internal movement like anger and desire. Therefore hatred of one's brother is a less grievous sin than murder.
I answer that, Sins committed against our neighbor are evil on two counts; first by reason of the disorder in the person who sins, secondly by reason of the hurt inflicted on the person sinned against. On the first count, hatred is a more grievous sin than external actions that hurt our neighbor, because hatred is a disorder of man's will, which is the chief part of man, and wherein is the root of sin, so that if a man's outward actions were to be inordinate, without any disorder in his will, they would not be sinful, for instance, if he were to kill a man, through ignorance or out of zeal for justice: and if there be anything sinful in a man's outward sins against his neighbor, it is all to be traced to his inward hatred.
On the other hand, as regards the hurt inflicted on his neighbor, a man's outward sins are worse than his inward hatred. This suffices for the Replies to the Objections.