each year, as she has stated, and her husband has no right to prevent her from doing so; for a husband may only forbid his wife from voluntary fasts, whereas a fast that has become obligatory and is tied to a fixed time is not something he may block. She has vowed to fast these specific days, so she must fulfil her vow.

If she says that she cannot manage the fast for health reasons, then—if what she means is merely that it is difficult for her—such hardship does not lift the obligation. Even if it is trying, she must fast, for she has bound herself to do so, and it is well known that fasting is taxing even for the strong.

But if what she means is that she is truly incapable of fasting, then in any year in which she is unable to fast because of illness or bodily weakness she should offer the expiation for an oath (kaffārat yamīn). Should she regain strength in a later year, the fast again becomes due, and so on.

She is not permitted to abandon what she has vowed, because she has made it binding upon herself. A Muslim must not trifle with vows—making a vow, obliging himself, and then seeking loopholes and stratagems—is not allowed, for once a vow is made it becomes one of the duties, and one may not free oneself from it without a legitimate Shar‘i excuse.

Question: If these days coincide with her monthly period, must she make them up later and pay an expiation, or what should she do?

Answer: If the fast falls during her menstrual period, she is excused from observing it, for this is one of the recognised Shar‘i excuses, like illness, and it lifts from her the duty of fasting on those days. However, if those days arrive while she is healthy and free from menstruation, the fast remains obligatory upon her.