menstruation, which by agreement is fifteen days. Subtracting this from the month leaves the minimum interval of purity: fifteen days. The other views have no basis in analogical reasoning; rather, they are derived from women’s customary experience. Whenever something requires a defined limit under Islamic law but no explicit text specifies it, recourse must be made to customary practice, as with wives’ maintenance and similar matters. Ahmad ibn al-Mu‘addal related that Ibn al-Mājishūn had encountered women whose interval of purity lasted five days, and had established this through the experience of a number of women.

The maximum duration of menstruation is fifteen days. The basis for this is the report that the Prophet (peace and blessings be upon him) addressed women, saying, “You are deficient in intellect and religion.” One of them asked, “How are our intellect and religion deficient, Messenger of Allah?” He replied, “One of you spends half her life—or one-half of her life—without praying. That is the deficiency in your religion.” He (peace and blessings be upon him) thus equated the time during which she prays with the time during which she does not, making them two equal halves. This entails that menstruation cannot exceed fifteen days each month. Since the hadith was expressed as a rebuke, it indicates that he intended to mention the longest period during which women refrain from prayer because of menstruation.

This is Mālik’s position and the underlying principle of his school. He also said that if a woman’s bleeding continues, she should allow an additional three days beyond her longest usual menstrual period as a precaution, then bathe, pray, and fast. He did not clarify whether her husband may have intercourse with her before the fifteen days are complete, with her being treated as a woman with irregular bleeding, or not. Our scholars have differed in their interpretations of his position on this matter.

Some held that her bathing after the additional precautionary days is a matter of juristic preference and precaution regarding prayer. Her husband may not have intercourse with her until she has completed fifteen days, when she must perform another, obligatory bath. This is indicated by Ibn Wahb’s narration from Mālik, in which he said, “I therefore thought it preferable to take the precaution of having her pray when prayer might not be obligatory for her, rather than have her omit prayer when it might be obligatory for her.” Since his position rests on precaution, precaution also requires abstaining from intercourse with her before the fifteen days are complete, requiring her to bathe when they are complete, and requiring her to make up her fasts.

Others held that once she has bathed, prayed, and fasted, her fasting is valid, her husband may have intercourse with her, and she is treated as a woman with irregular bleeding. Thus, she is not required to bathe upon completing fifteen days, except