Hadith 4483

(حديث مرفوع) حَدَّثَنَا إِسْمَاعِيلُ ، أَخْبَرَنَا أَيُّوبُ ، عَنْ نَافِعٍ ، عَنِ ابْنِ عُمَرَ أَنَّهُ قَالَ فِي عَاشُورَاءَ : " صَامَهُ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَأَمَرَ بِصَوْمِهِ ، فَلَمَّا فُرِضَ رَمَضَانُ تُرِكَ ، فَكَانَ عَبْدُ اللَّهِ لَا يَصُومُهُ ، إِلَّا أَنْ يَأْتِيَ عَلَى صَوْمِهِ " .
Sayyiduna Ibn Umar (may Allah be pleased with them both) regarding the fast of Ashura states that the Noble Prophet (peace and blessings be upon him) himself observed the fast on this day and also ordered others to fast on this day. When the fasts of Ramadan were made obligatory, this fast was abandoned. Sayyiduna Ibn Umar (may Allah be pleased with them both) himself would not fast on this day except when it coincided with his habitual fasting days.
Hadith Reference مسند احمد / مسند المكثرين من الصحابة / 4483
Hadith Grading حکم دارالسلام: إسناده صحيح، خ: 1892، م: 1126