Readings from the New Testament

When we have been harmed, it is best to not take revenge.

If someone has done you wrong, do not repay him with a wrong. Try to do what everyone considers to be good. Do everything possible on your part to live in peace with everybody. Never take revenge, my friends, but instead let God’s anger do it. For the scripture says, “I will take revenge, I will pay back, says the Lord.” Instead, as the scripture says: “If your enemies are hungry, feed them; if they are thirsty, give them a drink; for by doing this you will make them burn with shame.” Do not let evil defeat you; instead, conquer evil with good.
Romans 12.17-21

When we are angered, we must not harbor the anger but seek to forgive.

If you become angry, do not let your anger lead you into sin, and do not stay angry all day. Don’t give the Devil a chance. If you used to rob, you must stop robbing and start working, in order to earn an honest living for yourself and to be able to help the poor. Do not use harmful words, but only helpful words, the kind that build up and provide what is needed, so that what you say will do good to those who hear you. And do not make God’s Holy Spirit sad; for the Spirit is God’s mark of ownership on you, a guarantee that the Day will come when God will set you free. Get rid of all bitterness, passion, and anger. No more shouting or insults, no more hateful feelings of any sort. Instead, be kind and tender-hearted to one another, and forgive one another, as God has forgiven you through Christ.
Ephesians 4.26-32