Fulfilling a vow of obedience.

Question:
My wife made a vow that she would fast for a full, continuous month if the specific illness that the girl had did not appear, and praise be to Allah, the girl turned out to be healthy. She vowed to fast for a full month. Is she obligated to fulfill this vow for a continuous month?

Answer:
Answer: Yes, she is obligated to fast for a full month if the condition upon which she made the vow is fulfilled. You said that it was fulfilled, praise be to Allah, so she is obligated to fast. This is based on the saying of the Prophet (peace and blessings be upon him): “Whoever vows to obey Allah, let him obey Him, and whoever vows to disobey Allah (Mighty and Majestic), let him not disobey Him.” And Allah (Exalted and Majestic is He) said regarding the believers: “They fulfill their vows and fear a Day whose evil is widespread.” He the Exalted said: “And let them fulfill their vows and let them circumambulate the Ancient House.” And He the Exalted said: “And whatever you spend of an expenditure or vow of a vow, indeed Allah knows it, and there are no supporters for the wrongdoers.” So if a vow is a vow of obedience and the condition upon which it was made is fulfilled, then it is obligatory. Therefore, this woman is obligated to fast for a full month as she vowed.