Lajnah (Permanent Committee For Scholarly Research And Ifta’) was asked:
“A woman used to perform Sawm (Fast) during the six days of Shawwal every year. One year, she gave birth at the beginning of Ramadan and did not become ritually purified until after the end of Ramadan. She then made up for the days of Sawm she had missed. Does she also have to make up for the six days of Shawwal after making up for Ramadan days, even if it is not still Shawwal, or does she have to make up for Ramadan only? Is it obligatory to always fast the six days of Shawwal?”
“Performing Sawm for six days of Shawwal is a Sunnah (supererogatory act of worship following the example of the Prophet), not a Faridah (obligatory act), according to the saying of the Prophet (peace be upon him):
Anyone who fasts Ramadan and then follows it with six days of Shawwal it is as if they fasted the whole year. (Related by Imam Muslim in his Sahih [Authentic Book Hadith])
This Hadith is evidence that there is nothing wrong in fasting these days consecutively or separately, based on its general wording.
However, it is better to hasten and fast them, because the Noble Qur’an teaches saying:
…and I hastened to You, O my Lord, that You might be pleased.
The Qur’anic Ayahs and Hadith show that it is better to race and hasten to do good deeds. It is not obligatory to always fast these days, but it is better to do so, because the Prophet (peace be upon him) said: The deed liked most by Allah is one to which the doer adheres constantly, even if it is small. It is not prescribed to make up for these days after the end of Shawwal, because fasting them is a Sunnah whose time has passed, whether it was missed for a lawful excuse or not.
May Allah grant us success!” End quote. [Reference]
Note: Some of the scholars such as Shaykh Ibn Uthaymeen see that it can’t be made up unless due to a necessary reason.
AbdulFattaah Bin Uthman