Do Not Grieve Over the Hurt That Is Inflicted Upon You by Others, and Forgive Those That Have Ill-Treated You.
The price of jealousy and rancor is enormous; it is the price that the revengeful person pays in exchange for his malice towards others. He pays with his heart, flesh, and blood. His peace, his relaxation,and his happiness – these he forsakes because he desires the sweetness of revenge and because he resents others.
Jealousy and rancor are illnesses for which Allah has given the cure and remedy:
[Those] who repress anger, and who pardon men…
Show forgiveness, enjoin what is good, and turn away from the foolish [i.e. don’t punish them].
Repel [the evil] with one which is better [i.e. Allah ordered the faithful believers to be patient at the time of anger, and to excuse those who treat them badly], then verily! He, between whom and you there was enmity, [will become] as though he was a close friend.