"How excellent are the women of the Ansar. Modesty did not prevent them from seeking understanding of the religion."
نعم النساء نساء الأنصار، لم يكن يمنعهن الحياء أن يتفقهن في الدين.
Muslim narrated it in "Menstruation" (332) from the hadith of Shubah, from Ibrahim ibn Muhajir, who said, "I heard Safiyyah narrating from Ayesha," and he mentioned the hadith as part of a longer account that will come in full in the book of ghusl.