FORGIVENESS
Forbearing one another, and forgiving one another. If any man have a quarrel against any: even as Christ forgave you, so also do ye.
Colossians 3:13
Forgiving someone when they have offended, wronged, insulted, deceived, rejected, betrayed, disappointed or hurt you is a challenge, not only for new Christians, but for mature Christians as well. There is a tendency to want to get back at people so that they will feel as bad as you do or worse. Even if you don't get back at them you can end up hurting yourself more than the person that wronged you, when you hold on to your feellings.
Until you begin to operate in God's will concerning forgiveness you are allowing the devil to use you to contribute to your own bitterness, anger, hostility or depression. When God forgives you he also forgets, and doesn't hold what you've done against him over your head and continually remind you of your wrong doings. The most painful part of the offense is the memory itself. That's why you need to put it behind you as soon as possible.
And their sins and iniquities will I remember no more. Hebrews 10:17
God wants you to forgive and give the hurt and pain over to him. He doesn't wamt you to plan any vengeful acts against anyone.