Sahih Muslim Book - 13, Hadith - 2638

وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِى شَيْبَةَ وَأَبُو كُرَيْبٍ قَالاَ حَدَّثَنَا ابْنُ نُمَيْرٍ عَنْ هِشَامٍ بِهَذَا الإِسْنَادِ وَلَمْ يَذْكُرْ فِى أَوَّلِ الْحَدِيثِ وَكَانَ رَسُولُ اللَّهِ -صلى الله عليه وسلم- يَصُومُهُ. وَقَالَ فِى آخِرِ الْحَدِيثِ وَتَرَكَ عَاشُورَاءَ فَمَنْ شَاءَ صَامَهُ وَمَنْ شَاءَ تَرَكَهُ. وَلَمْ يَجْعَلْهُ مِنْ قَوْلِ النَّبِىِّ -صلى الله عليه وسلم- كَرِوَايَةِ جَرِيرٍ.

It was narrated from Hisham with this chain (a Hadith similar to no. 2637), but he did not say at the beginning of the hadith that the Messenger of Allah (SAW) used to fast (this day). And he said at the end of the Hadith: “He abandoned Ashura, so whoever wishes may leave it.” And he did not narrate it as the words of the Prophet (SAW) as jarir did.