about any good; it only extracts it from a miser.”

Accordingly, if a person makes a vow to perform an act of obedience—such as prayer, fasting, pilgrimage, or charity—he must then carry it out, for the Messenger of Allah ﷺ said, “Whoever vows to obey Allah, let him obey Him.” He ﷺ also said, “Fulfil your vow, for there is no fulfilment of a vow that involves disobedience to Allah.” Allah, Exalted and Glorified, has praised those who keep their vows.

This woman vowed to pray, but she did not specify which kind of prayer: was it voluntary prayers, or the obligatory prayers observed with constancy? If she meant the obligatory prayers, those are already incumbent on her by the Law itself, and her vow merely adds further emphasis.

If, however, she intended voluntary prayers, then she is required to perform whatever supererogatory prayers she can, except that she may not pray during her menstrual period. The days of menstruation are exempt and do not fall under her vow. Nevertheless, for added caution she may offer the expiation for an oath (kaffārat yameen) for that interval; she should give the expiation for an oath in respect of the menstruation days, while for all other times she must pray as she specified, thereby discharging her vow.

Question: It appears that what she intended was the obligatory prayers?

Answer: The obligatory prayers are already binding on her by the Law. When a person vows something that is already obligatory in the first place, the vow is valid but serves only as reinforcement. Thus, the prayers are incumbent upon her for two reasons: the ruling of the Law itself and her vow.