sixteen days, and its maximum has no limit (16); because the maximum period of purity has no limit. The common case is that it is the month known among people. So, if she knows that her month is thirty days, and that her menstruation within it is five days, and her purity is twenty-five, and she knows its beginning, then she is a possessor of a habit. If she knows the days of her menstruation and the days of her purity, she has known her month. But if she knows the days of her menstruation and does not know the days of her purity, or [knows] the days of her purity and does not know the days of her menstruation, then she is not a possessor of a habit. However, whenever she is ignorant of her month, we return her to the common case, so we assign her a period of menstruation in every month, just as we returned her in the count of the days of menstruation to six or to seven, because that is the common case.

Section: The third category of the types of women in the state of istihada (prolonged non-menstrual vaginal bleeding) is: she who has a habit and a faculty of discrimination (tamyiz). She is the one who had a habit and then experienced istihada, and her blood is distinguishable, some of it being black and some of it being red. If the black blood coincides with the time of her habit, then the habit and the discrimination have agreed in their indication, so both are acted upon. But if it is more or less than her habit and is suitable to be considered menstruation, there are two narrations [in the school]. One of them is that the discrimination is given precedence, so it is acted upon, and she abandons the habit; this is the apparent meaning of al-Khiraqi’s words, for he said: "She who possesses discrimination leaves prayer upon its appearance," and he did not distinguish between one who has a habit and one who does not. He stipulated, regarding returning her to the habit, that her blood must not be separated (17). This is the apparent view of the school of al-Shafi'i; because the quality of the blood is a sign inherent to it, while the habit is a time that has passed, and because it is an emission that necessitates ghusl, so it returns to its quality when there is ambiguity, like the case of semen. The apparent meaning of Ahmad’s words is the consideration of the habit. This is the opinion of the majority of the companions; because the Prophet (peace be upon him) returned Umm Habiba, and the woman who sought a legal ruling for her through Umm Salama, to the habit, and he did not distinguish or ask for further details regarding whether she was a possessor of discrimination or otherwise. As for the hadith of Fatima, it has been narrated that it returned her to the habit, and in another wording, it returned her to the discrimination, so the two narrations contradict each other (18), and the remaining hadiths remain free from any contradiction, so it is mandatory to act upon them. Furthermore, the hadith of