Recently I read a couple of Admonitions by St. Francis of Assisi that give what I have found to be a very liberating perspective on love of enemy.
11. That no one should be corrupted by the wickedness of anotherand:
No thing ought to displease the servant of God except sin. · And in whatever manner another person would sin, even on account of this the servant of God, out of charity, would not be upset or grow angry, (as one who) hoards up fault for himself (cf. Rm 2:5). · That servant of God, who does not grow angry nor disturbs himself on another's behalf, lives rightly without anything of his own. And blessed is he, who does not let anything remain for himself, rendering those things "which are Caesar's to Caesar, and those which are God's to God" (Mt 22:21).
9. On loveThe point is to value the state of your enemy's soul more than your own temporal good. Sounds simple. If someone sins against you they are doing themselves infinitely more harm than you. This reminds me of the section in Gaudium et spe about sins against the dignity of the person:
The Lord says: "Love your enemies; [do good to those who hate you, and pray on behalf of those who are persecuting and calumniating you]" (Mt 5:44). · For he truly loves his enemy, who does not grieve because of the injury, which he did to him, · but, concerning the sin against his own soul, burns for the sake of the love of God. And he shows love for him by (his) deeds.
Furthermore, whatever is opposed to life itself, such as any type of murder, genocide, abortion, euthanasia or wilful self-destruction, whatever violates the integrity of the human person, such as mutilation, torments inflicted on body or mind, attempts to coerce the will itself; whatever insults human dignity, such as subhuman living conditions, arbitrary imprisonment, deportation, slavery, prostitution, the selling of women and children; as well as disgraceful working conditions, where men are treated as mere tools for profit, rather than as free and responsible persons; all these things and others of their like are infamies indeed. They poison human society, but they do more harm to those who practice them than those who suffer from the injury. Moreover, they are supreme dishonor to the Creator (GS 27).I have often had time forgiving those who have injured me. I think from now on I'm going to remember these admonitions. I've always tried to pray for those who have injuried me, but I don't think I've gotten the point that my own injury is really nothing, that all that is important is the state of the soul who has done the injury.
Also, I think activists for justice should keep these admonitions in mind as well. We focus so much on the temporal effect of the injustice that we consider it "okay" to despise the perpetrator of the injustice. Not so. In fact, I'd say that if one is worked up about injustice, his first duty is to root out such contempt before he goes on to "fight" for justice.
I heard a paraphrase of a quote by Chesterton lately that seems relevant. Soldiers fight not because they hate those in front of them, but because they love those behind them.