Musnad Ahmad 31:72

Qutaybah ibn Sa'id narrated to us, Layth—meaning Ibn Sa'd—narrated to us, from Ibn al-Had, from 'Abdullah ibn Khabbab, from Abu Sa'id al-Khudri: That the Messenger of Allah, peace and blessings of Allah be upon him, had his uncle Abu Talib mentioned in his presence, so he said: "Perhaps my intercession will benefit him on the Day of Resurrection, so he will be placed in a shallow pool of fire that reaches his ankles, from which his brain will boil."