There are various fasts that Nabi (Sallallaahu Alayhi Wasallam) kept besides the fast of Ramadhan. The Sahaaba (Radhiallaahu Anhum) mention that, at times, Rasulullah (Sallallaahu Alayhi Wasallam) would fast so much that we thought he would not stop and at times he (Sallallaahu Alayhi Wasallam) did vice versa. (Sahih Bukhari Hadith1141, 1972) The Fuqaha (jurists) have classified them into 2 types; a) Sunnat and b) Mustahabb (preferable).
The fast of the 9th and 10th or 10th and 11th of Muharram has been classified as a Sunnah fast. (Durrul Mukhtar vol.2 pg.374; Maraaqiul Falaah pg.350). by fasting on the 10th, one year’s minor sins are forgiven. (Sahih Bukhari Hadith2000-2007; Sahih Muslim Hadith2838)
The following are those classified as Mustahabb (meritorious):
1. Every Tuesday and Thursday. (Maraaqiul Falaah pg.350; Aalamgiri vol.1 pg.201). Rasulullah (Sallallaahu Alayhi Wasallam) chose to fast these days because the deeds of the Ummah are presented to Allah Ta’ala on these 2 days. (Sahih Muslim; Sunan al-Tirmidhi Hadith745, 747; Sahih ibn Khuzaymah Hadith2116-2120)
2. 13th, 14th and 15th of every month which are known as Ayyaamul beedh. (Maraaqiul Falaah pg.350; Darrul Mukhtaar vol.2 pg.375; Aalamgiri vol.1 pg.201). One who observes these fasts every month will be rewarded as if he fasted his entire lifetime. (Musnad Ahmad vol.5 pg.140, 252; Sunan al-Tirmidhi Hadith762; Sahih ibn Khuzaymah Hadith2128). However, the 13th of the month of Dhul-Hijjah is excluded. (Imdaadul Fataawa)
3. Any three days of each month. (Shaami vol.2 pg.375; Tahtaawi alaa Maraaqil falah pg.350; Sahih al-Bukhari Hadith1981; Sahih Muslim Hadith2736, 2739; Sunan Abu Dawud; Sunan al-Tirmidhi Hadith742; Sahih ibn Khuzaymah Hadith2126). The reward of this fast is same as the previous, and in fact this one could be incorporated in the Ayyaamul beedh. (Shaami; Sahih ibn Khuzaymah vol.3 pg.303)
4. The 9th of Dhul-Hijjah which is the day of Arafaat. However, the Haaji who is in Arafaat is excluded, because he may be weakened through the fast. If this is not the case, then the Haaji may also keep this fast. (Durrul Mukhtaar vol.2 pg.375). Some Ulama have classified this as a Sunnah fast just like the 10th of Muharram. (Shaami vol.2 pg.375). By fasting on this day, 2 years minor sins will be forgiven. (Sahih al-Bukhari Hadith1988; Sahih Muslim Hadith2738-2739; Musnad Ahmad; Sunan Abu Dawud; Sahih ibn Khuzaymah Hadith2099, 2101)
5. Any 6 days of Shawwal (month after Ramadhaan). (Maraaqiul falaah pg.350; Aalamgiri vol.1 pg.201). The one who observes these fasts together with the fast of Ramadhaan, will receive the reward of fasting for the entire year. (Sahih Muslim Hadith2750; Musnad Ahmad; Sunan al-Tirmidhi Hadith759; Sunan Abu Dawud; Sahih ibn Hibbaan Hadith3634; Sahih ibn Khuzaymah Hadith2114)
6. On Fridays. (Shaami vol.2 pg.375; Maraaqiul falaah pg.350; Aalamgiri vol.1 pg.201). However, it is better to fast a day before it or after it as well. (Ibid; Shamaail al-Tirmidhi pg.288; Sahih ibn Khuzaymah Hadith1229; Sahih Muslim Hadith2678; al-Targheeb vol.2 pg.126)
7. Saturday and Sunday (together). (Shaami vol.2 pg.375-376 refer Musnad Ahmad vol.6 pg.323; Mustadrak al-Haakim; Sahih ibn Khuzaymah vol.3 pg.318 Hadith2167; Sahih ibn Hibbaan Hadith3616)
8. As much as possible in the first half of the month of Sha?baan with no specification on condition that one is confident that this will not weaken him for the fast of Ramadhaan. (Aalamgiri vol.1 pg.201 refer Sahih Bukhari Hadith1969; Sahih Muslim Hadith175, 176, 1156; Musnad Ahmad vol.6 pg.165; Sahih ibn Khuzaymah vol.3 pg.282-283; Sahih ibn Hibbaan Hadith3591)
9. Any or all of the first nine days of Dhul-Hijjah. (Aalamgiri vol.1 pg.201). The fast of each of these days is equal to the fast of one year. (Shu?ubul Imaan Hadith3758; Majma-uz-zawaaid vol.4 pg.20; Sunan al-Tirmidhi Hadith758)
10. As much as possible, in the month of Muharram. The best fast after Ramadhaan is the fast of Muharram (Sahih Muslim Hadith2748) and for each fast one will receive the reward of fasting for 30 days. (Tabrani; al-Targheeb vol.2 pg.114)
These are most of the fasts that Rasulullah (Sallallaahu Alayhi Wasallam), either observed himself or encouraged others to observe. Besides these, the Fuqahaa have stated that it is virtuous for one to fast as much as possible (if he has the strength to do so), for the fact that fasting is an act f worship in itself, hence, the more one does, the better.
Rasulullah (Sallallaahu Alayhi Wasallam) is reported to have said that the most beloved fasts to Allah is the fast of Daawood (alayhis salaam), he would fast every alternate day. (Sahih Bukhari Hadith1131; Sahih Muslim Hadith2731-2732). One should also bear in mind that it is forbidden to fast on the days of both Eids as well as the 11th, 12th, and 13th of Dhul-Hijjah. (Sahih Bukhari Hadith1990; Sahih Muslim Hadith2666-2672; Sahih ibn Khuzaymah Hadith2100; Shaami vol.2 pg.375)
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai