Answer:
In Sunan Ibn Majah it is narrated on the authority of Thauban (R.A.) that the Messenger (sallallahu alaihi wa sallam) said ““Whoever fasts for six days after (Eid) al-Fitr, it will be like the fasting of a year.” (Mirqaatul Mafatih: 4/545)
The scholars explain that the reason why fasting in Ramadan then fasting for six days in Shawwal is equal to fasting for a whole year is that each reward of a person is multiplied by ten. Therefore, fasting in Ramadan will be equal to fasting for 300 days (30 x 10 = 300); and fasting for an additional six days will be equal to fasting for 60 days (6 x 10 = 60). Fasting in Ramadan then for 6 days in Shawwal will altogether be equal to fasting for 360 days, which is the equivalent of one year. This is also supported by a hadith in Sunan Nisaa’i. (Sharh Muslim of Nawawi: 1/369; Ahsanul Fatawa: 4/440; Mirqaatul Mafatih: 4/544)
It thus becomes clear that the reward of fasting for a year is applicable to a person who keeps the fasts of Ramadan as well as six days of Shawwal. Therefore, it is not correct to say that if a person keeps 12 days of fasts in Shawwal instead of 6 days, he will get the reward of fasting for two years.
Mufti Faizal Riza
16/9/2011