the Prophet (peace and blessings be upon him) and his Companions are deemed invalid by hadith specialists. Nor do actual occurrences conform to a fixed rule. If someone knows only of menstruation lasting three days, another says that he knows of it lasting a day and a night. If someone knows only of it lasting a day and a night, another knows of it lasting a day. We cannot deny what we do not know. If we make what we know the limit prescribed by religious law, saying, “There is no menstruation lasting less than three days, a day and a night, or a day,” merely because that is all we know, we would be devising religious law ourselves on the basis of that knowledge. For lack of knowledge is not knowledge of nonexistence.

If this were truly a limit prescribed by religious law, the Messenger (peace and blessings be upon him) would have been better placed than us to know and explain it, just as he specified for the community the limits Allah had prescribed for them: the times of prayer, Hajj, and fasting; the designated places for Hajj; the minimum thresholds and prescribed dues of zakat; and the number of prayers and their bowings and prostrations. Had Allah and His Messenger prescribed a limit for menstruation, or for anything else whose limits the Prophet (peace and blessings be upon him) did not specify, the Messenger (peace and blessings be upon him) would have explained it. His not specifying a limit therefore indicates that he left the matter to what women recognize and what is called menstruation in ordinary language.

For this reason, when asked about menstruation, many of the early generations would say, “Ask the women, for they know more about it.” That is, they know what does and does not occur in menstruation. The religious ruling is attached to the term that denotes the actual occurrence. Thus, any bleeding that occurs is menstruation unless it is known to be blood from a vein or a wound. For the blood that emerges is either discharged by the womb, or bursts from one of the veins, or comes from the woman’s skin or