Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. Be kind to one another, tenderhearted, forgiving one another, as God in Christ forgave you.
There is nothing more destructive than holding a grudge. How many relationships have been destroyed by people who are unwilling to forgive? God places hand-picked people in our lives, how many have you let go of due to unforgiveness? Think of the mountain of sin that God has forgiven you, then forgive those people who God has placed in your life.