Abdu Samad reported: Al-Fudayl ibn ‘Iyad, may Allah have mercy on him, said, “If a man comes to you complaining about another man, then say: O brother, forgive him, as forgiveness is closer to righteousness. If he says my heart cannot tolerate forgiveness, but rather retaliation as Allah Almighty has commanded me, then say: If you must, do so in the best manner and retaliate with the same measure which you were afflicted, otherwise return to the door of forgiveness. Verily, the door of forgiveness is wider. Whoever forgives and sets things right, his reward is with Allah. The one who forgives will sleep comfortably in his bed and the one who avenges will toss and turn over his affairs.”
Source: Ḥilyat al-Awliyā’ 8/112
عن عَبْد الصَّمَدِ قَالَ قَالَ الْفُضَيْلَ بن عياض رحمه الله إِذَا أَتَاكَ رَجُلٌ يَشْكُوإِلَيْكَ رَجُلًا فَقُلْ يَا أَخِي اعْفُ عَنْهُ فَإِنَّ الْعَفْوَ أَقْرَبُ لِلتَّقْوَى فَإِنْ قَالَ لَا يَحْتَمِلُ قَلْبِي الْعَفْوَ وَلَكِنْ أَنْتَصِرُ كَمَا أَمَرَنِي اللهُ عَزَّ وَجَلَّ قُلْ فَإِنْ كُنْتَ تُحْسِنُ تَنْتَصِرُ مِثْلًا بِمِثْلِ وَإِلَّا فَارْجِعْ إِلَى بَابِ الْعَفْوِ فَإِنَّ بَابَ الْعَفْوِ أَوْسَعُ فَإِنَّهُ مَنْ عَفَا وَأَصْلِحْ فَأَجْرُهُ عَلَى اللهِ وَصَاحِبُ الْعَفْوِ يَنَامُ اللَّيْلَ عَلَى فِرَاشِهِ وَصَاحِبُ الِانْتِصَارِ يُقَلِّبُ الْأُمُورَ
8/112 حلية الأولياء وطبقات الأصفياء