Musnad Abu Ya'la al-Mawsili 149:129

Ibrahim narrated to us, Hammad narrated to us, from Abu Hamzah, from Ibrahim, from al-Aswad, from Aisha: That the Messenger of Allah (peace be upon him) was praying and he felt the cold. He said, "O Aisha, let down your garment (mirṭ) over me." She said, "I am menstruating." He said, "Come, and do not be stingy, for your menstruation is not in your hands."