A woman made a vow about three years ago, before she got married; she vowed to Allah, may He be exalted, that she would fast the first nine days of the month of Dhu’l-Hijjah every year. She was not aware that making vows is makrooh (disliked) and she does not remember whether she made an exception, saying that she would stop after she got married, or would refer the matter to her husband, or not. But now she has got married and her husband does not let her fast, because it is a naafil (supererogatory) fast and it is not permissible for her to observe this fast without his approval. Moreover, she is not able to fast for health reasons. She is asking whether she is obliged to continue with this vow to fast in the face of her husband’s opposition and her poor health, or does she have to offer an expiation for breaking an oath (kafaarat yameen) and rid herself of this obligation, or does she have to make it up later on at some other time, not fasting the days consecutively, or what should she do?

Praise
be to Allah.

Firstly: 

It should be pointed out that making vows
is makrooh or haraam, because it obliges the Muslim to do something that he
may not be able to do, or it may be very difficult for him to do when he is
fine without it. 

The Muslim should do good deeds, such as
fasting and other acts, without making vows, when he has the option of not
doing it if he so wishes. But if he makes a vow, he is obliging himself and
making it obligatory to fulfil his vow, if it is a vow to do an act of
obedience, because the Prophet (blessings and peace of Allah be upon him)
said: “Whoever makes a vow to do an act of obedience to Allah, let him do
it”; and he (blessings and peace of Allah be upon him) said: “Fulfil your
vows.” And Allah, may He be exalted, says (interpretation of the meaning)
“They (are those who) fulfill (their) vows” [al-Insaan 76:7]; “Then let them
… perform their vows” [al-Hajj 22:29]
; “And whatever you spend for
spendings (e.g., in Sadaqah – charity, etc. for Allahs Cause) or whatever
vow you make, be sure Allah knows it all” [al-Baqarah 2:270]

If a person does make a vow, and it is a
vow to do an act of obedience, then he is obliged to act upon it, but if he
has not already made a vow, the Muslim should not oblige himself or make a
vow. 

What the questioner mentions, about having
made a vow to fast the first nine days of Dhu’l-Hijjah on a permanent basis,
is a vow to do an act of obedience and she is obliged to fulfil it. Her
husband does not have the right to prevent her from doing that, because her
husband may only prevent her from observing voluntary fasts. But in the case
of obligatory fasts that are connected to a specific time, it is not
permissible for her husband to prevent her from doing it. She made a vow to
fast these specific days, so she must fulfil that vow. If she says that she
is not able to do it for health reasons, if what she means is that it is
difficult for her, that does not mean that she should not do what has become
obligatory, even if it is difficult for her; so she should fast, because she
has obliged herself to do that. It is well-known that fasting may be
difficult even for one who is strong. 

But if what she means is that she cannot
fast, then in the year in which she is not able to fast because of sickness
or physical weakness, she must offer expiation for breaking an oath (kafaarat
yameen). Then if she becomes stronger in the following year, she must fast,
and so on. 

Therefore it is not permissible for her to
not do what she vowed to do, because she has obliged herself to do that. The
Muslim should not take the matter of vows lightly, making a vow and obliging
himself to do something, then after that looking for ways out and tricks to
avoid doing it. This is not permissible, because what one vows to do becomes
an obligatory duty, and it is not permissible to not do it without a
legitimate shar‘i reason. 

If those days coincide with her monthly
period, then she is excused for not fasting them, because this is a
legitimate shar‘i excuse, such as if she falls sick. This excuse waives the
obligation of fasting on those days, but if those days come and she has no
legitimate shar‘i excuse, in the sense that she is in good health and is not
menstruating, then she must fast them.