Musnad Ahmad 32:1272

'Abd al-Samad narrated to us, Hammad narrated to us, from Thabit, from Anas, that Umm Ayman wept when the Messenger of Allah, peace and blessings of Allah be upon him, passed away. It was said to her, "What makes you weep for the Prophet, peace and blessings of Allah be upon him?" She said, "I indeed knew that the Prophet, peace and blessings of Allah be upon him, would die, but I only weep for the revelation that has been lifted from us."