seventeen days (1). Al-Shafi'i has two opinions, corresponding to the two narrations regarding its minimum and maximum. Ishaq ibn Rahwayh said: 'Ata' said: "Menstruation is one day." Sa'id ibn Jubayr said: "Its maximum is thirteen days." Al-Thawri, Abu Hanifah, and his two companions said: "Its minimum is three days, and its maximum is ten," based on what Wathilah ibn al-Asqa' reported, that the Prophet (may Allah bless him and grant him peace) said: "The minimum of menstruation is three days, and its maximum is ten (2)." Anas said: "A woman's menstrual period is three, four, five, six, seven, eight, nine, or ten (3)." Anas would not say that except as a matter of religious authority (tawqifan). Malik ibn Anas said: "There is no limit to its minimum; it may be just one hour, because if there were a limit to its minimum, a woman would not cease praying until that limit had passed."

Our view is that it has been mentioned in the Shari'ah in an absolute sense without specification, and there is no limit for it in the language nor in the Shari'ah, therefore it is necessary to refer in this matter to custom ('urf) and habit ('adah), just as in the cases of possession (qabd), safeguarding (ihraz), separation (tafarruq), and the like. It has been found that menstruation can conventionally occur for one day. 'Ata' said: "I have seen women who menstruate for a day, and others who menstruate for fifteen days." Ahmad said: "Yahya ibn Adam told me, saying: I heard Sharik say: 'We have a woman among us who menstruates every month for fifteen days in a continuous flow.'" Ibn al-Mundhir said: "Al-Awza'i said: 'We have a woman among us who menstruates in the morning and becomes pure in the evening. They consider it menstruation for which she ceases prayer.'" Al-Shafi'i said: "I saw a woman, and it was established to me regarding her that she never ceased menstruating for one day without exceeding it, and it was established to me regarding other women that they never ceased menstruating for less than three days." Ishaq ibn Rahwayh mentioned from Bakr ibn Abd Allah al-Muzani that he said: "My wife menstruates for two days." Ishaq said: "A woman from our family who is well-known said: 'I have not broken my fast during the month of Ramadan for twenty years except for two days.'"

Their statement must be accepted, due to the saying of the Exalted: {And it is not lawful for them to conceal what Allah has created in their wombs} (4). Were it not for the fact that their statement is acceptable, He would not have forbidden them to conceal it, and this is treated in the same manner as His saying: {And do not conceal testimony} (6).