Sahih Muslim 2647
صحيح مسلم#2647Sahihوَحَدَّثَنَا أَحْمَدُ بْنُ عُثْمَانَ النَّوْفَلِيُّ، حَدَّثَنَا أَبُو عَاصِمٍ، حَدَّثَنَا عُمَرُ بْنُ مُحَمَّدِ بْنِ، زَيْدٍ الْعَسْقَلاَنِيُّ حَدَّثَنَا سَالِمُ بْنُ عَبْدِ اللَّهِ، حَدَّثَنِي عَبْدُ اللَّهِ بْنُ عُمَرَ، - رضى الله عنهما - قَالَ ذُكِرَ عِنْدَ رَسُولِ اللَّهِ صلى الله عليه وسلم يَوْمُ عَاشُورَاءَ فَقَالَ " ذَاكَ يَوْمٌ كَانَ يَصُومُهُ أَهْلُ الْجَاهِلِيَّةِ فَمَنْ شَاءَ صَامَهُ وَمَنْ شَاءَ تَرَكَهُ " .
Abdullah b. Umar (Allah be pleased with them) reported that the day of 'Ashura was mentioned before the Messenger of Allah (ﷺ) and he said:It is a day when the people in the pre-Islamic days need to observe fast, so he who wishes to observe fast should do so, and he who wishes to abandon it should do so
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: 13:153