وَعَنْهُ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: ((صُومُوا يَوْمَ عَاشُورَاءَ وَخَالِفُوا فِيهِ الْيَهُودَ وَصُومُوا قَبْلَهُ يَوْمًا أَوْ بَعْدَهُ يَوْمًا))
Narrated by Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Observe fasting on the Day of Ashura, but oppose the Jews in this matter, and that is by fasting a day before it or a day after it.