Musnad Ahmad 908:15

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Ishaq, from Harithah ibn Mudarrib, who said: I entered upon Khabbab, and he had been cauterized. He said: "I do not know of anyone who has encountered such trials as I have encountered. I used to be in a state where I could not find a single dirham during the time of the Messenger of Allah (peace and blessings of Allah be upon him), and now I have forty thousand in the corner of this house of mine." "And were it not that the Messenger of Allah (peace and blessings of Allah be upon him) forbade us, or forbade that we wish for death, I would have wished for it."