Third question of Fatwa no.
10447
Q 3: I had a friend who was ill,
and I vowed that I would observe Sawm (Fast) for one month if she recovered. This was before I got married. allah, all praise be to Him alone, in fact cured my friend after I got married.
The point is that since I married I am either involved in a pregnancy or breastfeeding. I am no longer able to observe Sawm; what should I do?
A:
It is Wajib (obligatory) on you to fulfill the vow that you made, for it is a vow to do an act of obedience to Allah (Exalted be He). Moreover, it is authentically reported that the Prophet (peace be upon him) said:
Whoever vows to obey Allah, must obey Him.
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'