Sahih Muslim
Sahih Muslim 1162 d
Book 13: The Book of Fasting
Chapter 36 It is recommended to fast three days of every month, and to fast on the days of 'Arafah and 'Ashura', and to fast on Mondays and Thursdays
باب اسْتِحْبَابِ صِيَامِ ثَلَاثَةِ أَيَّامٍ مِنْ كُلِّ شَهْرٍ وَصَوْمِ يَوْمِ عَرَفَةَ وَعَاشُورَاءَ وَالِاثْنَيْنِ وَالْخَمِيسِ
Sahih Muslim 1162 d
This hadith has been narrated by Ghailan b. Jarir with the same chain of transmitters, but with one variation, that there has been made mention of Monday and not of Thursday.
وَحَدَّثَنِي أَحْمَدُ بْنُ سَعِيدٍ الدَّارِمِيُّ، حَدَّثَنَا حَبَّانُ بْنُ هِلاَلٍ، حَدَّثَنَا أَبَانُ الْعَطَّارُ، حَدَّثَنَا غَيْلاَنُ بْنُ جَرِيرٍ، فِي هَذَا الإِسْنَادِ بِمِثْلِ حَدِيثِ شُعْبَةَ غَيْرَ أَنَّهُ ذَكَرَ فِيهِ الاِثْنَيْنِ وَلَمْ يَذْكُرِ الْخَمِيسَ .
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