Musnad Ahmad 1153:1533

'Abd al-Rahman and 'Affan narrated to us, they said: Abu 'Awanah narrated to us, from Ibrahim ibn Muhajir, from Safiyyah bint Shaybah, from 'Aishah, who said: She mentioned the women of the Ansar and praised them, and said: "They have a good quality." She said: "When Surat al-Nur was revealed, they took their waist-wrappers—or the waist-wrappers of their garments—and tore them, then they made veils out of them." And a woman among them entered upon the Messenger of Allah (peace and blessings of Allah be upon him) and said: "O Messenger of Allah, inform me about purification from menstruation." He said: "Yes, let one of you take her water and her lotus leaves, then let her purify herself, then let her perform the purification well, then let her pour [water] over her head, then let her press upon the roots of her hair, then let her rub it, for that is purification. Then let her pour water over herself, then let her take a piece of cloth scented with musk and purify herself with it." She said: "O Messenger of Allah, how do I purify myself with it?" The Messenger of Allah (peace and blessings of Allah be upon him) used a metaphor for that. 'Aishah said: "Follow with it the trace of the blood." 'Affan said: "Then let her pour water over her head, and let her press the roots of her hair and rub it." 'Affan said: "To the waist-wrapper or waist-wrappers."