forgiveness

Never speak disparagingly of others, but praise without distinction. Pollute not your tongues by speaking evil of another. Recognize your enemies as friends, and consider those who wish you evil as the wishers of good. You must not see evil as evil and then compromise with your opinion, for to treat in a smooth, kindly way one whom you consider evil or an enemy is hypocrisy, and this is not worthy or allowable. You must consider your enemies as your friends, look upon your evil-wishers as your well-wishers and treat them accordingly. Act in such a way that your heart may be free from hatred. Let not your heart be offended with anyone. If some one commits an error and wrong toward you, you must instantly forgive him. Do not complain of others. Refrain from reprimanding them, and if you wish to give admonition or advice, let it be offered in such a way that it will not burden the bearer. 
(‘Abdu'l-Baha, from a talk, December 2, 1912, ‘The Promulgation of Universal Peace: Talks Delivered by 'Abdu'l-Bahá during His Visit to the United States and Canada in 1912’)