Sayyidah Aisha (may Allah be pleased with her) said: The Quraysh used to fast on the day of Ashura in the pre-Islamic period. Then the Messenger of Allah (peace and blessings be upon him) also ordered fasting on this day, until the fasting of Ramadan was made obligatory. Then the Messenger of Allah (peace and blessings be upon him) said: Whoever wishes may fast on the day of Ashura, and whoever wishes may leave it.
Hadith Referenceاللؤلؤ والمرجان / كتاب الصيام / 688
Hadith Gradingمحدثین:«صحیح»
Hadith Takhrij«صحیح، أخرجه البخاري في: 30 كتاب الصوم: 1 باب وجوب صوم رمضان»