' The quality of forgiveness '...

The quality of forgiveness that burns up all things except beauty is the quality of love.

Bowl of Saki, by Hazrat Inayat Khan
Commentary by Pir-o-Murshid Inayat Khan:

Nature is such that no two things are created alike; and the human being cannot expect his or her mate, whom nature made, to be as docile and flexible as that creature whom his imagination alone conceives. To make a friend, forgiveness is required which burns up all things, leaving only beauty.

Love is the fire that burns all infirmities. ... By criticizing, by judging, by looking at wickedness with contempt, one does not help the wicked or the stupid person. The one who helps is he who is ready to overlook, who is ready to forgive, to tolerate, to take disadvantages he may have to meet with patiently.

To resist evil, however, usually means to participate in and be guilty of the same evil. There is a story told of Muhammad, that a man who had always maligned him and behaved as a bitter and treacherous enemy, came to see him. His disciples, hoping for revenge, were disappointed and indignant to find that Muhammad treated his despicable enemy with courtesy, even deference, granting his request.

'Did you not see the gray in his beard?' asked Muhammad after the man had gone. 'The man is old, and his age at least called for my courtesy.' It is forgiveness and that forbearance which is a recognition of the freedom and dignity of the human being, that consume all ugliness and burn up all unworthiness, leaving only beauty there.