Amr bin Ali bin Bahr al-Bahli narrates from Muhammad bin Fadayl bin Ghazwan narrating from Asim al-Ahwal narrating from Anas bin Malik.

Narrated Anas: When the reciters of Qur'an were martyred, Allah's Apostle recited Qunut for one month and I never saw him (i.e. Allah's Apostle) so sad as he was on that day.

حَدَّثَنَا عَمْرُو بْنُ عَلِيٍّ، حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ، حَدَّثَنَا عَاصِمٌ الأَحْوَلُ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ قَنَتَ رَسُولُ اللَّهِ صلى الله عليه وسلم شَهْرًا حِينَ قُتِلَ الْقُرَّاءُ، فَمَا رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم حَزِنَ حُزْنًا قَطُّ أَشَدَّ مِنْهُ‏.‏