Q: Is it permissible to fast all 10 days of Dhul-Hijjah?
A: It is recommended to fast the “10 days of Dhul-Hijjah” (specifically the first 9) according to the hadith, “There are no days, in which righteous deeds are done, more beloved to Allah than in these 10 days”. The most emphasized of those 10 is the Day of Arafat. Fasting that day is an expiation for two years based on the hadith narrated by Muslim which states, “I reckon that Allah will pardon the year before it and the year after it”. In al-Furu’, it was said, what is intended here are the minor sins. If they have no minor sins, their major sins will be reduced. If they have no major sins, they will be elevated in degrees. Sharh al-Muntaha