Musnad Ahmad 32:1647

'Affan narrated to us, Hammad narrated to us, from Thabit, from Anas ibn Malik, that Umm Ayman wept when the Prophet, may Allah bless him and grant him peace, died. It was said to her, "Do you weep?" She said, "By Allah, I knew indeed that the Messenger of Allah, may Allah bless him and grant him peace, would die, but I only weep for the revelation that has been cut off from us from the heaven."