Sahih Muslim Book 1, Hadith Number 409.

Chapter : Intercession of the Messenger of Allah (may peace be upon him) for Abu Talib and some remission for him on this account.

Abdullah b. al-Harith reported: I heard Abbas say: I said: Messenger of Allah, verily Abu Talib defended you and helped you; would it be beneficial for him? He (the Holy Prophet) said: Yes; I found him in the lowest part of the Fire and I brought him to the shallow part.