Jesus commanded us to love. The Catholic Church teaches that respecting life is more than just not hurting other people. We must actively work for peace and justice, even for those we are in conflict with.
Our enemies can be global in nature, such as terrorists. But more often they are local. The person who was a bully. The person who spread gossip. The person who excluded me. In all of these cases, we are not to give in to hatred and the desire for revenge.
Deliberate hatred is contrary to charity. Hatred of the neighbor is a sin when one deliberately wishes him evil. Hatred of the neighbor is a grave sin when one deliberately desires him grave harm.Catechism of the Catholic Church 2303
God desires the conversion of our enemies. And praying for our enemies also helps us to convert our own hearts, away from hatred and toward peace. While it is right to be angry about injustice, we cannot let that anger turn to hatred.
Instead of working for vengeance we must truly work for peace. While it is appropriate to recognize and identify wrongs, it is not appropriate to desire to hurt the person who has wronged us.
Anger is initially a natural emotion, a reaction to perceived injustice. If anger becomes hatred, however, and someone has ill-will toward his neighbor, this normal feeling becomes a serious offense against charity. All uncontrolled anger, especially thoughts of revenge, are detrimental to peace and destroy “the tranquility of order”.Youcat – Youth Catechism of the Catholic Church 396
God wishes that every single person be saved. And God loves the person who wronged me, just as he loves me. He asks us to learn to forgive. And Jesus gave us the example of praying for his enemies from the cross.
Then Jesus said, “Father, forgive them, they know not what they do. “Luke 23:34
So we are called to be more like our savior. We must promote peace and truly desire that all God’s children know the love of God.
The intercession of Christians recognizes no boundaries: “for all men, for kings and all who are in high positions,” for persecutors, for the salvation of those who reject the Gospel.Catechism of the Catholic Church 2636
We must truly forgive those who have hurt us. Through prayer, our own hearts and the hearts of our enemies can be transformed.
For more information on this topic, refer to the full text in the Catechism of the Catholic Church about peace (2302-2306) and about intercessory prayer (2634-2636). Also read Matthew 5:38-48. A youth-oriented explanation can be found in Youcat – Youth Catechism of the Catholic Church (395-399).