Question : What is the ruling on fasting six days of Shawwaal? Is it waajib (obligatory)?
Answer: Praise be to Allaah.
Fasting six days of Shawwaal after the obligatory fast of Ramadaan is Sunnah Mustahabbah, not waajib. It is recommended for the Muslim to fast six days of Shawwaal, and in this there is great virtue and an immense reward.
«Whoever fasts these six days will have recorded for him a reward as if he had fasted a whole year» [reported in a hasan hadeeth from the Prophet (peace and blessings of Allaah be upon him)]
«من صام ستة أيام بعد الفطر متتابعة فكأنما صام الدهر السنة كلها»
Abu Ayyoob (may Allaah be pleased with him) reported that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: «Whoever fasts Ramadaan and follows it with six days of Shawwaal, it will be as if he fasted for a lifetime». [Narrated by Muslim, Abu Dawood, al-Tirmidhi, al-Nisaa’i and Ibn Maajah]
«من صام رمضان ثم أتبعه ستا من شوال كان كصيام الدهر»
رواه مسلم وأصحاب السنن الأربعة
The Prophet (peace and blessings of Allaah be upon him) explained this when he said: «Whoever fasts for six days after (Eid) al-Fitr has completed the year: (whoever does a good deed (hasanah) will have ten hasanah like it)».
«من صام ستة أيام بعد الفطر ، كان تمام السنة ، من جاء بالحسنة فله عشر أمثالها»
According to another report: «Allaah has made for each hasanah ten like it, so a month is like fasting ten months, and fasting six days completes the year» [al-Nisaa’i and Ibn Maajah. See also Saheeh al-Targheeb wa’l-Tarheeb, 1/421].
«جعل الله الحسنة بعشر أمثالها ، الشهر بعشرة أشهر ، و صيام ستة أيام بعد الشهر تمام السنة»
رواه النسائي وابن ماجه.
It was also narrated with the wording: «Fasting for the month of Ramadaan brings the reward of ten like it, and fasting for six days brings the reward of two months, and that is the fasting of the whole year»
«صيام شهر رمضان بعشرة أشهر وصيام ستة أيام بشهرين فذلك صيام السنة»
The Hanbali and Shaafa’i fuqaha’ explained that fasting six days of Shawwaal after fasting Ramadan makes it as if one has fasted for an entire year of obligatory fasts, because the multiplication of the reward applies even to naafil fasts, because each hasanah brings the reward of ten like it. [i.e.one Ramadan is equivalent to ten months of fasting, and the clincher, six days, is equal to two months, (6×10=60).Thus completes the year’s twelve months.]
Another benefit of the important benefits of fasting six days of Shawwaal is that is makes up for any shortfall in a person’s obligatory Ramadan fasts, because no one is free of shortcomings or sins that have a negative effect on his fasting. On the Day of Resurrection, some of his naafil deeds will be taken to make up the shortcomings in his obligatory deeds, as the Prophet (peace and blessings of Allaah be upon him) said:
«The first thing for which people will be brought to account on the Day of Resurrection will be their salaah (prayer). Our Lord, may He be glorified and exalted, will say to His angels – although He knows best – ‘Look at the salaah of My slave, whether it is complete or incomplete.’ If it is perfect, it will be recorded as perfect, and if something is lacking, He will say, ‘Look and see whether My slave did any voluntary (naafil) prayers.’ If he did some voluntary prayers, [Allaah] will say, Complete the obligatory actions of My slave from his voluntary actions.’ Then all his actions will be dealt with in a similar manner» [Narrated by Ibn Majjah]
« إن أول ما يحاسب به العبد المسلم يوم القيامة الصلاة المكتوبة فإن أتمها وإلا قيل انظروا هل له من تطوع فإن كان له تطوع أكملت الفريضة من تطوعه ثم يفعل بسائر الأعمال المفروضة مثل ذلك»
رواه ابن ماجه .