What is the ruling on a woman who vowed to fast every Monday and Thursday, and what should she do if her period arrives?

The questioner : Peace be upon you.

The Shaykh : Peace be upon you and Allah's mercy.

The questioner : Honorable Shaykh, a woman has encountered a problem. She vowed that if this problem is resolved favorably, she would fast every Monday and Thursday continuously for the rest of her life. As you know, she has her monthly period and other impediments to fasting. What should she do?

The Shaykh : In the name of Allah, the Most Gracious, the Most Merciful. Praise be to Allah, Lord of the worlds. May Allah send prayers and blessings upon our Prophet Muhammad, his family, his Companions, and those who follow them in excellence until the Day of Judgment. She is required to fulfill her vow by fasting on Mondays and Thursdays. If her period coincides with these days, she makes them up in the second week. For example, if her period starts on Sunday and she becomes pure on Friday, she fasts on Saturday and Sunday for the previous week.

The questioner : And if she is unable to, Honorable Shaykh? Yes, and if she is unable to.

The Shaykh : If she is unable to, then it is looked at: if this inability is temporary, such as an illness, she waits until she is able and makes up the fasts. If it is continuous, she feeds one poor person for every day.

The presenter : Okay, thank you, Shaykh. Yes. May Allah reward you with good.