قَالَ هُشَيْمٌ أَخْبَرَنَا ابْنُ أَبِي لَيْلَى عَنْ دَاوُدَ بْنِ عَلِيٍّ عَنْ أَبِيهِ عَنْ جَدِّهِ ابْنِ عَبَّاسٍ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ صُومُوا يَوْمَ عَاشُورَاءَ وَخَالِفُوا فِيهِ الْيَهُودَ صُومُوا قَبْلَهُ يَوْمًا أَوْ بَعْدَهُ يَوْمًا
مسند امام احمد بن حنبل · Hadith 2154
It was narrated from Dawood bin’ AlI, from his father, that his grandfather Ibn 'Abbas (RA) said: The Messenger of Allah (PBUH) said: "Fast the day of ' shoora' but be different from the Jews; fast one day before it or one day after it."
Translated by Dr. Muhammad Muhsin Khan · Reviewed by Islamic University of Madinah · Published March 2020