Dear respected Shaykh, assalamu alaikum wa rahmatullahi wa barakatuh. What is the Sunnah concerning fasting the day of ‘Ashurah? Is it fasting a day before ‘Ashurah or a day after it? صيام يوم عاشوراء

Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions. Wa alaikum assalam wa rahmatullahi wa barakatuh. As to what follows: In response to your question, we say:   The Sunnah in fasting the day of ‘Ashurah is fasting on the tenth of Muharram because of what Muslim narrated in his Sahih from the hadith of Abu Qatadah that the Prophet (peace be upon him) said, “I hope that the fast of ‘Ashurah will expiate for the sins of the past year” [Muslim (1162)]. Al-Bukhari transmitted that ‘Ubaidullah ibn Abi Yazid heard ibn ‘Abbaas being asked about fasting on the day of ‘Ashurah and he said, “I do not know that the Prophet fasted any day because of its virtue, except this day" meaning the day of ‘Ashurah” [al-Bukhari (2600)]. This is the opinion of the majority of the scholars. It is recommended to fast on  the ninth of Muharram in addition to the tenth because of what was transmitted by Muslim in his Sahih from the hadith of ibn ‘Abbas (may Allah be pleased with him) that “when the Messenger of Allah (peace be upon him) fasted on the day of ‘Ashurah and commanded that it should he observed as a fast, they (his Companions) said to him: “O Messenger of Allah! It is a day which the Jews and Christians hold in high esteem”. Thereupon the Messenger of Allah (peace be upon him) said: “When the next year comes, God willing, we will observe fast on the ninth, but the Messenger of Allah (peace be upon him) died before the advent of the next year.” [Muslim (1134)]. The majority of the scholars are of the opinion that the Messenger of Allah wanted to fast on the ninth and the tenth so as to be different from the Jews and Christians. Thus, it becomes clear from this that the Sunnah in fasting the day of ‘Ashurah is to fast the ninth and tenth of Muharram, and that whoever fasts on the tenth of Muharram only attains the virtue of fasting on that day. There is no evidence that can be relied upon for what was mentioned by ibn al-Qayyim and ibn Hajar that the highest degree of fasting the day of ‘Ashurah is to fast for three days; the tenth of Muharram, a day before it and a day after it. And Allah knows best.