Sahih al-Bukhari 3943
Sahih al-Bukhari · Book 63: Merits of the Helpers in Madinah (Ansaar) · The coming of the Jews to the Prophet (saws) on his arrival at Al-Madina
Narrated Ibn `Abbas:
حَدَّثَنَا زِيَادُ بْنُ أَيُّوبَ ، حَدَّثَنَا هُشَيْمٌ ، حَدَّثَنَا أَبُو بِشْرٍ ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ لَمَّا قَدِمَ النَّبِيُّ صلى الله عليه وسلم الْمَدِينَةَ وَجَدَ الْيَهُودَ يَصُومُونَ عَاشُورَاءَ، فَسُئِلُوا عَنْ ذَلِكَ، فَقَالُوا هَذَا الْيَوْمُ الَّذِي أَظْفَرَ اللَّهُ فِيهِ مُوسَى وَبَنِي إِسْرَائِيلَ عَلَى فِرْعَوْنَ، وَنَحْنُ نَصُومُهُ تَعْظِيمًا لَهُ، فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " نَحْنُ أَوْلَى بِمُوسَى مِنْكُمْ ". ثُمَّ أَمَرَ بِصَوْمِهِ.
When the Prophet (ﷺ) arrived at Medina he found that the Jews observed fast on the day of 'Ashura'. They were asked the reason for the fast. They replied, "This is the day when Allah caused Moses and the children of Israel to have victory over Pharaoh, so we fast on this day as a sign of glorifying it." Allah's Messenger (ﷺ) said, "We are closer to Moses than you." Then he ordered that fasting on this day should be observed.