To al-Haarith al-Hamdani
Nahj al-Balāgha|Volume 1|Book 2|Chapter 69
وَاكْظِمِ الْغَيْظَ، وَتَجَاوَزْ عِنْدَ الْمَقْدَرَةِ، وَاحْلُمْ عِنْدَ الْغَضَبِ، وَاصْفَحْ مَعَ الدَّوْلَةِ، تَكُنْ لَكَ الْعَاقِبَةُ.
Kill your anger and forgive when you have power (to punish). Show forbearance in the moment of rage, and pardon in spite of authority; the eventual end will then be in your favour.