Musnad Ahmad 33:366

'Abd al-Samad narrated to us, Mahdi narrated to us, Wasil narrated to us, from Abu al-Zubayr, from Jabir, who said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, three days before his death, saying: "Let not any one of you die except while he is thinking well of his Lord."