It is a day on which the people of pre-Islamic days observed fast. So he who liked to fast on this day should do so, and he who liked to abandon it should abandon it. 'Abdullah (Allah be pleased with him) did not observe fast except when it coincided (with the days when he was in the habit of observing voluntary fasts during every month).
وَحَدَّثَنِي مُحَمَّدُ بْنُ أَحْمَدَ بْنِ أَبِي خَلَفٍ، حَدَّثَنَا رَوْحٌ، حَدَّثَنَا أَبُو مَالِكٍ، عُبَيْدُ اللَّهِ بْنُ الأَخْنَسِ أَخْبَرَنِي نَافِعٌ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، - رضى الله عنهما - قَالَ ذُكِرَ عِنْدَ النَّبِيِّ صلى الله عليه وسلم صَوْمُ يَوْمِ عَاشُورَاءَ . فَذَكَرَ مِثْلَ حَدِيثِ اللَّيْثِ بْنِ سَعْدٍ سَوَاءً .
Abdullah b. Umar (Allah be pleased with them) reported that the day of 'Ashura was mentioned before the Messenger of Allah (ﷺ) and he narrated a hadith like one (narrated above).
It is a day when the people in the pre-Islamic days need to observe fast, so he who wishes to observe fast should do so, and he who wishes to abandon it should do so.
When al-Ash'ath b. Qais entered the house of 'Abdullah he was having his breakfast. He ('Abdullah b. Umar) said: Abd Muhammad (al-Asha'th), come near to the breakfast. Thereupon he said: Is not today the day of 'Ashura? He ('Abd al-Rahman) said: Do you know what the day of 'Ashura is? He said: What is it? He said: It is a day on which the Messenger of Allah (ﷺ) used to observe fast before the (fasting) in the month of Ramadan (became) obligatory. But when it became obligatory the (fasting of 'Ashura) was abandoned (as compulsory). Abu Kuraib said: He (the Holy Prophet) abandoned it.
Abu Abd al-Rahman, it is the day of 'Ashura (and you are eating). Upon this he said: Fast was observed on (this day) before the (fasting) in Ramadan was made obligatory, but when it was made obligatory, (fasting on the day of 'Ashura) was abandoned. So if you are not fasting, then take food.
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُوسَى، أَخْبَرَنَا شَيْبَانُ، عَنْ أَشْعَثَ، بْنِ أَبِي الشَّعْثَاءِ عَنْ جَعْفَرِ بْنِ أَبِي ثَوْرٍ، عَنْ جَابِرِ بْنِ سَمُرَةَ، - رضى الله عنه - قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَأْمُرُنَا بِصِيَامِ يَوْمِ عَاشُورَاءَ وَيَحُثُّنَا عَلَيْهِ وَيَتَعَاهَدُنَا عِنْدَهُ فَلَمَّا فُرِضَ رَمَضَانُ لَمْ يَأْمُرْنَا وَلَمْ يَنْهَنَا وَلَمْ يَتَعَاهَدْنَا عِنْدَهُ .
Jabir b Samura reported that the Messenger of Allah (ﷺ) commanded us to observe fast on the day of Ashura and exhorted us to do it and was particular about it But when (fasting) in Ramadan was made obligatory, he hence. forth neither commanded us nor forbade us, nor was he so particular about it.
People of Medina, where are your scholars? I heard the Messenger of Allah (ﷺ) say on this very day: It is the day of 'Ashura. Allah has not made fasting on This day obligatory for you but I am fasting. He who likes to observe fast among you should do so, and he who likes not to observe it may not observe it.