Abu Ya'qub said: "It has become clear from the statement of Ibn Sirin—where he says: 'Women know better about that'—that she recognizes her own constitution and nature. Furthermore, in what we have described regarding the Prophet's (peace be upon him) words to the women who experienced istihada (abnormal uterine bleeding) during his time, for whom he gave each one a different legal opinion (fatwa) than the others, it is evident that menstruation in women differs in this regard. He did not restrict them to adhering to a single specific time as the end of their menstruation—as these people have done.
If menstruation had a beginning and an end—as these people say: 'Three days is the minimum and ten is the maximum'—the Prophet (peace be upon him) would have clarified that to some of them and would not have left them in uncertainty regarding it.
Everyone knows that counting numbers is easier for them in terms of calculation than being tasked with determining the onset (iqbal) and the cessation (idbar) of the menstrual period. How, then, could a scholar find it acceptable to set a specific time for her when the Prophet (peace be upon him) left that matter to them without a fixed time, as he said to them: 'When the menstruation begins,' and: 'When it ceases'? If the onset and cessation were not something they could comprehend, the Prophet (peace be upon him) would not have tasked them with it; he would have said to them—had a time limit been permissible in that regard, as these people have timed it—'Remain for such-and-such days, and do not exceed that.'
Have you heard that any one of them responded to the Prophet (peace be upon him) regarding what she heard from him by saying: 'I do not understand what you have described to me!'? In this, there is evidence that the Prophet (peace be upon him) addressed them with what they comprehended and understood.
In what was said regarding the woman experiencing istihada, there is evidence for the negation of a fixed number; where he said: 'If she sees the fresh, bright blood that is unmistakable,' it is known that this is something understood by women. Do you not see what al-Awza'i said: 'The onset of menstruation is the blackness of the blood, its odor, and its change; this does not persist with a woman, for if it were to persist with her, it would kill her'? Thus, al-Awza'i interpreted the onset and cessation, although Malik ibn Anas interpreted the onset as the appearance of blood—even if it were only the amount of a single drop—he considered it menstruation, to the extent that if she discharged even a single occurrence of fresh blood during Ramadan, she would refrain from fasting and abandon prayer; and he interpreted the cessation as purity, saying: Whenever she sees blood, she abandons prayer, and when she sees purity, she prays."
