Musnad Ahmad 1153:1897

Al-Zuhri said: Urwah, or Amrah, informed me from Aisha, who said: The Messenger of Allah, peace and blessings of Allah be upon him, said during his illness in which he died: "Pour over me from seven water skins whose ties have not been loosened, so that I may find relief and then give instructions to the people." Aisha said: So we seated him in a tub belonging to Hafsa, made of copper, and we poured the water over him from them until he began to signal to us that you have done enough. Then he went out.