Musnad Ahmad 1153:1901

Abu Mu'awiyah narrated to us, he said: Al-A'mash narrated to us, from Thabit ibn 'Ubayd, from Al-Qasim ibn Muhammad, from 'Aishah, she said: The Messenger of Allah, peace and blessings of Allah be upon him, said to me: "Hand me the prayer mat from the mosque." She said: So I said: "I am menstruating." He said: "Indeed, your menstruation is not in your hand."