Musnad Ahmad 31:480

Qutaybah ibn Sa'id narrated to us, Layth narrated to us, from Ibn al-Had, from 'Abdullah ibn Khabbab, from Abu Sa'id al-Khudri, that the Messenger of Allah (may Allah bless him and grant him peace) 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 is placed in a shallow pool of fire that reaches his ankles, from which his brain boils."