The third question of Fatwa no.
17797
Q 3: A man vowed to observe Sawm (Fasting) for one month for the Sake of Allah (Exalted be He), but without determining within himself whether he would fast it successively or separately. What is the ruling of Shari‘ah (Islamic law) on this? Is it obligatory for him to fast it successively or is he permitted to fast it separately?
A:
If
the person who made the vow to observe Sawm for one month did not specify how he would fast it, it will be permissible for him to fast it successively or separately. However, if he intended it to be successive, or stated it, or determined a specific month, it will be obligatory for him to fast it successively, unless he determines to fast the month of Rajab, as the Sawm of the month of Rajab is Makruh (reprehensible), and in such case he will have to offer a Kaffarah (expiation) for a broken oath.
May Allah grant us success! May peace and blessings be upon our Prophet Muhammad, his family and Companions!
Permanent Committee for Scholarly Research and Ifta’