Muwatta Malik, Book 2, Hadith 133 (In-Book)

Yahya related to me from Malik from Hisham ibn Urwa from his father that A'isha, the wife of the Prophet, may Allah bless him and grant him peace, said, "I used to comb the head of the Messenger of Allah, may Allah bless him and grant him peace, while I was menstruating."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّهَا قَالَتْ كُنْتُ أُرَجِّلُ رَأْسَ رَسُولِ اللَّهِ صلى الله عليه وسلم وَأَنَا حَائِضٌ ‏.‏

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also referenced under: Book 2, Hadith 104 (USC-MSA)