حَدَّثَنَا ابْنُ أَبِي عُمَرَ، حَدَّثَنَا سُفْيَانُ، عَنْ عَاصِمٍ، قَالَ سَمِعْتُ أَنَسًا، يَقُولُ مَا رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم وَجَدَ عَلَى سَرِيَّةٍ مَا وَجَدَ عَلَى السَّبْعِينَ الَّذِينَ أُصِيبُوا يَوْمَ بِئْرِ مَعُونَةَ كَانُوا يُدْعَوْنَ الْقُرَّاءَ فَمَكَثَ شَهْرًا يَدْعُو عَلَى قَتَلَتِهِمْ .
Never did I ace the Messenger of Allah (ﷺ) so much grieved (at the loss of a) small army as I saw him grieved at those seventy men who were called" reciters" (and were killed) at Bi'r Ma'una; and he invoked curse for full one month upon their murderers.
Source: Sahih Muslim — repository translation · Imam Muslim ibn al-Hajjaj al-Naysaburi — authenticity/grade metadata requires independent source review · Sunnah.comAudio not available for the selected reciter.
Source: Sahih Muslim — repository arabic · Imam Muslim ibn al-Hajjaj al-Naysaburi · Sunnah.com