حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ حَدَّثَنَا سُفْيَانُ حَدَّثَنَا أَيُّوبُ السَّخْتِيَانِيُّ عَنْ ابْنِ سَعِيدِ بْنِ جُبَيْرٍ عَنْ أَبِيهِ عَنْ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا أَنَّ النَّبِيَّ صَلَّی اللَّهُ عَلَيْهِ وَسَلَّمَ لَمَّا قَدِمَ الْمَدِينَةَ وَجَدَهُمْ يَصُومُونَ يَوْمًا يَعْنِي عَاشُورَائَ فَقَالُوا هَذَا يَوْمٌ عَظِيمٌ وَهُوَ يَوْمٌ نَجَّی اللَّهُ فِيهِ مُوسَی وَأَغْرَقَ آلَ فِرْعَوْنَ فَصَامَ مُوسَی شُکْرًا لِلَّهِ فَقَالَ أَنَا أَوْلَی بِمُوسَی مِنْهُمْ فَصَامَهُ وَأَمَرَ بِصِيَامِهِ
صحیح بخاری · Hadith 3397
Narrated Ibn `Abbas: When the Prophet came to Medina, he found (the Jews) fasting on the day of 'Ashura' (i.e. 10th of Muharram). They used to say: "This is a great day on which Allah saved Moses and drowned the folk of Pharaoh. Moses observed the fast on this day, as a sign of gratitude to Allah." The Prophet said, "I am closer to Moses than they." So, he observed the fast (on that day) and ordered the Muslims to fast on it.
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020