a man slandered one of his forefathers from the time of the Jahiliyyah, and Al-'Abbas slapped him. His people came and said: "Let him slap him as he slapped him," and they prepared for quarrel. News of that reached the Prophet, and he ascended the Minbar and said: "O People, which of the people of the Earth do you know to be the most noble before Allah?" They said: "You." He said: "Al-Abbas belongs to me and I to him. Do not defame our dead or offend our living." Those people came and said: "O Messenger of Allah, we seek refuge with Allah from your anger; pray to give us." (Using translation from Nasāʾī 4775)  

أَنَّ رَجُلًا وَقَعَ فِي أَبٍ كَانَ لَهُ فِي الْجَاهِلِيَّةِ فَلَطَمَهُ الْعَبَّاسُ فَجَاءَ قَوْمَهُ فَقَالُوا لَيَلْطِمَنَّهُ كَمَا لَطَمَهُ فَلَبِسُوا السِّلَاحَ فَبَلَغَ ذَلِكَ النَّبِيَّ ﷺ فَصَعِدَ الْمِنْبَرَ فَقَالَ «أَيُّهَا النَّاسُ أَيُّ أَهْلِ الْأَرْضِ تَعْلَمُونَ أَكْرَمُ عَلَى اللهِ؟» قَالُوا أَنْتَ قَالَ «فَإِنَّ الْعَبَّاسَ مِنِّي وَأَنَا مِنْهُ لَا تَسُبُّوا أَمْوَاتَنَا فَتُؤْذُوا أَحْيَاءَنَا» فَجَاءَ الْقَوْمُ فَقَالُوا يَا رَسُولَ اللهِ نَعُوذُ بِاللهِ مِنْ غَضَبِكَ اسْتَغْفِرْ لَنَا