Hadith 4:494
Abu Mu'awiyah narrated to us, from al-A'mash, from 'Umarah, from 'Abd al-Rahman ibn Yazid, who said: Al-Ash'ath ibn Qays entered upon 'Abdullah while he was eating lunch. He said, "O Abu Muhammad, come near to my lunch." He said, "Is today not the day of 'Ashura?" He said, "And do you know what the day of 'Ashura is?" He said, "And what is it?" He said, "It is only a day that the Messenger of Allah, may Allah bless him and grant him peace, used to fast before the month of Ramadan was revealed to him. Then, when the month of Ramadan was revealed, he abandoned it."
حدثنا أبو معاوية عن الأعمش عن عمارة عن عبد الرحمن بن يزيد قال دخل الأشعث بن قيس على عبد الله وهو يتغدى قال يا أبا محمد ادن إلى غدائي فقال أو ليس اليوم يوم عاشوراء فقال وهل تدري ما يوم عاشوراء فقال وما هو قال إنما هو يوم كان رسول الله صلى الله عليه وسلم يصومه قبل أن ينزل عليه شهر رمضان فلما نزل شهر رمضان تركه