Sahih Muslim 1550
صحيح مسلم#1550Sahihحَدَّثَنَا 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 .
Asim reported - I heard Anas saying: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
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 5:383