or for purification that is not recommended; and whether or not an impurity has fallen into it, provided that any such impurity is known to have undergone transformation and been wholly absorbed into it. If, however, traces of the impurity remain apparent in the water, using it is forbidden, because that amounts to using something forbidden.

Section

Another example is the term menstruation. Allah has attached numerous rulings to it in the Quran and Sunnah, yet neither its minimum nor its maximum duration has been specified, nor the duration of the interval of purity between two menstrual periods, despite how commonly this affects the Muslim community and their need to know its rulings. Nor does the language distinguish between one duration and another. Whoever fixes a limit in this matter has therefore contradicted the Quran and Sunnah. Some scholars set both a maximum and a minimum duration, though they disagree over those limits.

Others set a maximum but no minimum. The third view is the most correct: there is neither a minimum nor a maximum duration. Rather, whatever bleeding a woman experiences as a consistent, recurring pattern is menstruation. Even if it lasts less than a day, if that remains her consistent pattern, it is menstruation. Likewise, if its maximum duration is seventeen days and that remains her consistent pattern, it is menstruation.

If, however, she bleeds continuously without interruption, this is known not to be menstruation. For both revealed Law and language establish that a woman is sometimes free of menstruation and sometimes menstruating, and that her state of purity has its rulings, while her menstruation has its rulings.