The Book of Fasting
13/19. Chapter:
Fasting on the day of Ashura'
Sahih Muslim
وَحَدَّثَنَاهُ ابْنُ بَشَّارٍ، وَأَبُو بَكْرِ بْنُ نَافِعٍ جَمِيعًا عَنْ مُحَمَّدِ بْنِ جَعْفَرٍ، عَنْ شُعْبَةَ، عَنْ أَبِي بِشْرٍ، بِهَذَا الإِسْنَادِ وَقَالَ فَسَأَلَهُمْ عَنْ ذَلِكَ، .
This hadith has been narrated by Ibn Bishr with the same chain of transmitters (but with a slight variation) that he (the Holy Prophet) inquired of them (Jews) about it (fasting on the day of 'Ashura).
Reference : Sahih Muslim 1130bIn-book reference : Book 13, Hadith 163USC-MSA web (English) reference : Book 6, Hadith 2519