Colossians 3:13(New International Reader's Version)
13 Put up with each other. Forgive the things you are holding against one another. Forgive, just as the Lord forgave you.
What causes the most damage in relationships? It's un-forgiveness. No matter what has happened between people, lack of forgiveness has the affect of causing the most distress that we can ever experience in our lives. Not forgiving one who has hurt and wronged you can last your entire life; it can cause problems that are physical, mental, and spiritual. Nothing is sadder than seeing someone who has been "eaten up" by un-forgiveness; it is evident to all who gets to know that person.
The Christian community is not immune to this, although it probably can be much more damaging. Un-forgiveness can be harmful to someone's entire Christian life, because it affects the person's walk by keeping it from being genuine. In doing this their growth in the faith is stunted; they will be living against the main premise of their own salvation. Through Jesus Christ, God completely forgives us of all of our wrongdoing, when we accept His gift of salvation. The Bible says that "He has removed our sins as far as the East is from the West"(Psalm 103:12), and that "He remembers them no more"(Isaiah 43:25). For us to forgive another any less than God has forgiven us, will cause us to lose out on our own forgiveness(Matthew 6:14-15).
For us to truly walk in the image of Christ, we need to have a heart that easily forgives. Yes, we do get hurt, but we need to always remember that if Jesus could forgive those who crucified Him, who are we to not forgive an offense to us. True Christianity is exhibited by true forgiveness. And what is forgiveness? It is forgetting that we have been wronged; exhibiting love for those who hurt us and being Christ-like in our behavior towards them. This is not easy, and it can only be done through the power of the Holy Spirit that lives in us.
Is there someone who so wronged you that you still can't forgive them? Surrender your un-forgiveness to God, embrace that person in Christ's love, and soon you will forget what has been done to you.
32 Be kind and loving to each other, and forgive each other just as God forgave you in Christ. Ephesians 4:32 (New Century Version)