Fasting on the Day of ‘Arafah
Abu Hafsah, may Allah be pleased with him, reported that the Prophet, upon whom be peace, said:
“Fasting on the Day of ‘Arafah absolves the sins for two years: the previous year and the coming year, and fasting on ‘Ashura, (the tenth day of Muharram) atones for the sins of previous years.”
Reported by all except Al-Bukhari and At-Tirmidhi
In another saying the Prophet’s wife Hafsah, may Allah be pleased with her, said:
“Four things the Messenger of Allâh never neglected: Observing fast on the day of ‘Ashura, ‘Arafat, three days every month, and offering fajr sunnah prayers early in the morning.”
Muslim