Hadith on Fasting: Sins erased by fasting Arafat, Ashura

Abu Qatadah reported: The Prophet, peace and blessings be upon him, was asked about fasting the day of Arafat and he said, “It will expiate the sins of the previous and upcoming years.” Then, the Prophet was asked about fasting the day of Ashura and he said, “It will expiate the sins of the past year.”

Source: Ṣaḥīḥ Muslim 1162

Grade: Sahih (authentic) according to Muslim

عَنْ أَبِي قَتَادَةَ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ سُئِلَ عَنْ صَوْمِ يَوْمِ عَرَفَةَ فَقَالَ يُكَفِّرُ السَّنَةَ الْمَاضِيَةَ وَالْبَاقِيَةَ وَسُئِلَ عَنْ صَوْمِ يَوْمِ عَاشُورَاءَ فَقَالَ يُكَفِّرُ السَّنَةَ الْمَاضِيَةَ

1162 صحيح مسلم كتاب الصيام باب استحباب صيام ثلاثة أيام من كل شهر وصوم يوم عرفة وعاشوراء والاثنين والخميس