Ishaq said: "Many aspects of women's menstruation have appeared problematic to scholars, and regarding that which is problematic, caution and relying on certainty is safer, for the Prophet, may Allah bless him and grant him peace, commanded that doubts be avoided, and that one should seek to safeguard one's religion."
566 - Yahya ibn 'Abd al-Hamid narrated to us, saying: Shurayk narrated to us, from Abu al-Yaqzan, from 'Adi ibn Thabit, from his father, from his grandfather, from the Prophet, may Allah bless him and grant him peace, who said: "The woman experiencing istihada leaves off prayer for the days of her periods (aqra') during which she used to menstruate, then she performs ghusl, performs wudu for every prayer, and fasts and prays."
567 - Ishaq narrated to us, saying: Al-Nadr ibn Shumayl and Wahb ibn Jarir informed us, both saying: Shu'bah narrated to us, from 'Uthman—the freed slave of Banu Hashim—who said: I heard Ibn 'Abbas—when he was asked about the woman experiencing istihada—say: "She leaves off prayer for the days of her menstruation, then she performs ghusl, performs wudu for every prayer, and let her use a pad (li-tastathfir); for it is only a vein and a strike from Satan." It was said to him: Even if it is flowing? He said: "Even if it flows like a spout."
Chapter: The Color of Menstrual Blood in Istihada
I asked Ishaq, and I said: A woman whose period of purity was twenty days, and sometimes it was twenty-five, and sometimes it was thirty days, then she experienced istihada; how should she act? He said: "If a woman's menstruation is clear as to how many days it lasts, then she experiences istihada, and she does not know what removed her from her [usual] menstruation, then she should sit for the days she used to menstruate before the affliction that befell her. Menstrual blood is a dark blood that is known. If it becomes murky, yellowish, or 'tariyyah' (a specific type of discharge), and she has exceeded her days of menstruation at that time, she is then a woman in a state of istihada; she performs ghusl when the time of her menstruation passes, performs wudu for every prayer, prays, fasts Ramadan, and her husband may have intercourse with her during the state of istihada; and that is because prayer is more sacred than intercourse."
Ishaq said: "Menstruation may advance and may delay."
(1) Thus it is in the original, and the correct reading is "'Ammar," and he is Ibn Abi 'Ammar al-Makki. (2) Thus it is in the original, and the correct reading is "tariyyah."
