21 – Abū al-Haytham narrated from Yūsuf ibn Māhak, from Ḥafṣah, the wife of the Prophet ﷺ, that a woman came to her and said, “My husband approaches me from behind, and I dislike it.” When this was conveyed to the Prophet ﷺ, he said, “There is no harm in it so long as it is through a single passage.”