It was narrated that 'Aishah said:
"The Messenger of Allah said to me: 'Get me a mat from the mosque.' I said: 'I am menstruating.' He said: 'Your menstruation is not in your hand.'" (IT)
English reference (IT): Vol. 1, Book 1, Hadith 632 (IT)
Arabic reference (IT): Book 1, Hadith 675 (IT)