Muwatta Malik #133
Purity
The Arabic includes the chain of narration (sanad) and the collector's commentary; the English translation shows the Prophet's words only.
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 .
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."
About Muwatta Malik
This hadith is #133 from Muwatta Malik, in the Book of Purity.