Section I: Mustahabb Fasting (Voluntary Fasting)

Firstly: Defining voluntary
Tatawwu` linguistically: It is to donate.
Tatawwu` terminologically: It is seeking closeness to Allah, exalted, with non-wajib acts of worship.

Secondly: Ruling of the intention in voluntary fasts
The intention is a condition for voluntary fasting. Consensus has been quoted over this by: Ibn Rushd, Ibn Qudamah, and al-Nawawi.

Thirdly: Time of the intention
This has been discussed in the ruling of the overnight intention in voluntary fasting.

Fourthly: Unconditional voluntary fasting
It is mustahabb to fast unconditional voluntary fasts, so long as it is not days which are not haram to fast.

Fifthly: Fasting the six days of Shawwal
It is a sunnah to fast six days of Shawwal after fasting Ramadan. This is the position of al-Shafi`i, Ahmad, Dawud, the majority of late Hanafis, and the position of many scholars.

Sixthly: First eight days of Dhu al-Hijjah
It is mustahabb to fast the first eight days of Dhu al-Hijjah. This is by agreement of the four schools of jurisprudence, and it is the position of the Zahiris.

Seventhly: Fasting `Arafah for the non-pilgrim
It is mustahabb to fast `Arafah for the non-pilgrim, and it is the ninth of Dhu al-Hijjah. This is by agreement of the four schools of jurisprudence, and it is the position of the Zahiris.

Eighthly: Fasting Muharram
It is mustahabb to fast Muharram, and this is by agreement of the four schools of jurisprudence.

Ninthly: Fasting `Ashura'
It is mustahabb to fast `Ashura', and it is the tenth day of Muharram. Consensus has been quoted over this by: Ibn Rushd, al-Nawawi, Ibn Hajar, and al-`Ayni.

Tenthly: Fasting a day before `Ashura' (Tasu`a')
It is mustahabb to fast a day before `Ashura', and that is the ninth day of Muharram. This is by agreement of the four schools of jurisprudence.

Eleventhly: Fasting most of Sha`ban
It is mustahabb to fast most of Sha`ban, and this is the position of the majority: Hanafis, Malikis, Shafi`is, and a group of the Salaf.

Twelfthly: Fasting Mondays and Thursdays
It is mustahabb to fast Mondays and Thursdays every week. This is by agreement of the four schools of jurisprudence, and it is the position of the Zahiris.

Thirteenthly: Fasting three days of every month
It is mustahabb to fast three days of every month. This is by agreement of the four schools of jurisprudence, and it is the position of the Zahiris and the majority of scholars.

Fourteenthly: Fasting the white days
The majority of jurists preferred that the three fasted days of each month match the white days. [818] They are the thirteenth, fourteenth, fifteenth of every Arabic month, named so because the moon is full on those days. Both Ayyam al-Bid and al-Ayyam al-Bid are valid. This is the position of the Hanafis, Shafi`is, Hanbalis, and a group of the Malikis.

Fifteenthly: Fasting every other day
It is mustahabb to fast every other day, and this is the overall summarised position. [819] We stated ‘overall’ since there are days that are prohibited to fast, like the two Eids and the days of celebration in Dhu al-Hijjah, and other days where scholars have differed. Ibn Hazm has quoted consensus over this.

Sixteenthly: Voluntary fasting of a single day
Whoever fasts a single day for the sake of Allah, exalted, he is rewarded for it. This is the overall summarised position. [820] As long as it is not a prohibited day. Ibn Hazm has quoted consensus on this.