Musnad Ahmad 1153:2331

Ya'qub narrated to us, he said: My father narrated to us, from Ibn Ishaq, from Salih ibn Kaysan, from al-Zuhri, from Ubayd Allah ibn Abd Allah ibn Utbah, that Aisha said: The Messenger of Allah, peace and blessings of Allah be upon him, had a black *khamisah* (garment) upon him when his pain became severe. She said: He would place it upon his face at one time, and uncover it from his face at another time, and he would say: "May Allah fight a people who took the graves of their prophets as places of worship." He was forbidding that for his nation.