Matthew 6:14-15
For if ye forgive men their trespasses, your heavenly Father will also forgive you: But if ye forgive not men their trespasses, neither will your Father forgive your trespasses.
It is important for us to forgive the people in our lives that wrong us. It can be very hard to do this at times, but it is important. The act of forgiveness also helps us heal. We cannot fully heal from our past without forgiveness. If we expect Christ to forgive us of our shortcomings, we should do the same thing to others.