due to the saying of Allah the Exalted: {When you divorce women, divorce them for their waiting period} (35). When Ibn Umar divorced his wife while she was menstruating, the Prophet (may Allah bless him and grant him peace) commanded him to take her back and keep her until she became pure (36). Among them is that it prevents the validity of purification, because her state of impurity (hadath) remains. Among them is that it necessitates the major ritual bath (ghusl) upon its cessation, due to his saying (peace be upon him): 'Wait for the duration of the time your period used to hold you back, then perform ghusl and pray.' Agreed upon (37). It is a sign of puberty, due to his saying (peace and blessings be upon him): 'Allah does not accept the prayer of a menstruating woman except with a khimar (head covering) (38).' The waiting period (iddah) is not completed for the divorced woman and those like her except by it, due to his saying the Exalted: {And divorced women shall wait by themselves for three menstrual periods (quru')} (39). Most of these rulings are agreed upon among the scholars of the Ummah. Once this is established, there is a necessity to understand menstruation, so that what pertains to it from the rulings can be known. Ahmad, may Allah have mercy on him, said: 'Menstruation revolves around three hadiths: the hadith of Fatimah, the hadith of Umm Habiba, and the hadith of Hamna.' In another narration: 'the hadith of Umm Salama' in place of the hadith of Umm Habiba. We shall mention these hadiths and others in their proper places, if Allah the Exalted wills.

91 - Issue: He said: (The minimum duration of menstruation is a day and a night, and its maximum is fifteen days).

This is the correct view according to the school of Abu Abdullah. Al-Khallal said: 'The school of Abu Abdullah has no disagreement that the minimum of menstruation is one day, and its maximum is fifteen days.' It was also narrated from him that its maximum is seventeen days (1).