"Abu Umamah saw heads (of the Khawarij) hanging on the streets of Damascus. He said: 'The dogs of the Fire and the worst dead people under the canopy of the heavens. The best dead men are those whom these have killed.' He then recited: On the Day when some faces will become white and some faces will become black... (3:106) until the end of the Ayah. I said to Abu Umamah: 'Did you hear it from the Messenger of Allah ﷺ?' He said: 'If I had not heard it but one time, or two times, or three times, or four times - until he reached seven - I would not have narrated it to you.'" (Using translation from Tirmidhī 3000)   

أَنُهْ رَأَى رُءُوسًا مَنْصُوبَةً عَلَى دَرَجِ مَسْجِدِ دِمَشْقَ فَقَالَ أَبُو أُمَامَةَ كِلَابُ النَّارِ كِلَابُ النَّارِ ثَلَاثًا شَرُّ قَتْلَى تَحْتَ أَدِيمِ السَّمَاءِ خَيْرُ قَتْلَى مَنْ قَتَلُوهُ ثُمَّ قَرَأَ {يَوْمَ تَبْيَضُّ وُجُوهٌ وَتَسْوَدُّ وُجُوهٌ} [آل عمران 106] 10 قُلْتُ لِأَبِي أُمَامَةَ أَسَمِعْتَهُ مِنْ رَسُولِ اللهِ ﷺ؟ قَالَ لَوْ لَمْ أَسْمَعْهُ إِلَّا مَرَّتَيْنِ أَوْ ثَلَاثًا أَوْ أَرْبَعًا أَوْ خَمْسًا أَوْ سِتًّا أَوْ سَبْعًا مَا حَدَّثْتُكُمْ