Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
ahmad:26068 – Rawḥ > Muḥammad b. Abū Ḥafṣah > Ibn Shihāb > ʿUrwah > ʿĀʾishah > Kānūā Yaṣūmūn Yawm ʿĀshūrāʾ Qabl

The people used to fast on 'Ashura (the tenth day of the month of Muharram) before the fasting of Ramadan was made obligatory. And on that day the Kaʿba used to be covered with a cover. When Allah made the fasting of the month of Ramadan compulsory, Messenger of Allah ﷺ said, "Whoever wishes to fast (on the day of 'Ashura') may do so; and whoever wishes to leave it can do so." (Using translation from Bukhārī 1592)  

أحمد:٢٦٠٦٨ – حَدَّثَنَا رَوْحٌ قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي حَفْصَةَ قَالَ حَدَّثَنَا ابْنُ شِهَابٍ عَنْ عُرْوَةَ عَنْ عَائِشَةَ قَالَتْ كَانُوا يَصُومُونَ يَوْمَ عَاشُورَاءَ قَبْلَ

أَنْ يُفْرَضَ رَمَضَانُ وَكَانَ يوماً فِيهِ تُسْتَرُ الْكَعْبَةُ فَلَمَّا فَرَضَ اللهُ ﷻ رَمَضَانَ قَالَ رَسُولُ اللهِ ﷺ مَنْ شَاءَ أَنْ يَصُومَهُ فَلْيَصُمْهُ وَمَنْ شَاءَ أَنْ يَتْرُكَهُ فَلْيَتْرُكْهُ  

See similar narrations below:

Collected by Bukhārī
bukhari:1592 – Yaḥyá b. Bukayr > al-Layth > ʿUqayl > Ibn Shihāb > ʿUrwah > ʿĀʾishah > Muḥammad b. Muqātil > ʿAbdullāh > Ibn al-Mubārak > Muḥammad b. Abū Ḥafṣah > al-Zuhrī > ʿUrwah > ʿĀʾishah > Kānūā Yaṣūmūn ʿĀshūrāʾ Qabl

The people used to fast on 'Ashura (the tenth day of the month of Muharram) before the fasting of Ramadan was made obligatory. And on that day the Kaʿba used to be covered with a cover. When Allah made the fasting of the month of Ramadan compulsory, Messenger of Allah ﷺ said, "Whoever wishes to fast (on the day of 'Ashura') may do so; and whoever wishes to leave it can do so."  

البخاري:١٥٩٢ – حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ حَدَّثَنَا اللَّيْثُ عَنْ عُقَيْلٍ عَنِ ابْنِ شِهَابٍ عَنْ عُرْوَةَ عَنْ عَائِشَةَ ؓ وَحَدَّثَنِي مُحَمَّدُ بْنُ مُقَاتِلٍ قَالَ أَخْبَرَنِي عَبْدُ اللَّهِ هُوَ ابْنُ الْمُبَارَكِ قَالَ أَخْبَرَنَا مُحَمَّدُ بْنُ أَبِي حَفْصَةَ عَنِ الزُّهْرِيِّ عَنْ عُرْوَةَ عَنْ عَائِشَةَ ؓ قَالَتْ كَانُوا يَصُومُونَ عَاشُورَاءَ قَبْلَ

أَنْ يُفْرَضَ رَمَضَانُ وَكَانَ يَوْمًا تُسْتَرُ فِيهِ الْكَعْبَةُ فَلَمَّا فَرَضَ اللَّهُ رَمَضَانَ قَالَ رَسُولُ اللَّهِ ﷺ مَنْ شَاءَ أَنْ يَصُومَهُ فَلْيَصُمْهُ وَمَنْ شَاءَ أَنْ يَتْرُكَهُ فَلْيَتْرُكْهُ