Many of the articles have to do with holding people accountable, establishing blame, and getting those scales even again. Forgiveness seeks another way. The king does not say that. It means that the hurt which has been done, or the debt which has been incurred to you no longer has power over you. You can look at a person who has hurt you and see new possibilities, new life.
Forgiveness seeks a change in the person and in the community.
Jesus wanted us to see that the path to a life with God is paved with the stones of forgiveness. You may remember that after his resurrection, Jesus gave his disciples and therefore, the church, the power to forgive. It is the essential part of our ministry in Christ. Our work together is to forgive. It's hard to remember that when many Christians seems to spend their time and efforts in judging - judging who's in and out, who's right and wrong, who has sinned and who has not.