Holding grudges against painful is our problem. We carry the weight while the guy who hurt us may have long moved on with his life. We probably have all different techniques to let go of the past, but for me as a mind-driven person, understanding does the job. I find it easy to forgive and move on if I understand where people come from. Sometimes I accept my wound and wait for the piece of the puzzle that explains why the past happened the way it did. This piece of the puzzle always comes; it is just a question of time, and until that moment I simply give the wound a time-out. The past is not fixed. It is as alive as the future and it is determined by the intention of the present moment. Ask the past to be healed and the Holy Spirit will move earth and Heavens to make it so.
Even more powerful than understanding is empathy. They say don’t judge a brother before you have walked a mile in his shoes. It is easy to forgive if we one day stepped into the same trap. Having plenty of life experience gives power to the art of forgiving.