Musnad Ahmad 21:1

Waki’ narrated to us, Sufyan narrated to us, from ‘Abd al-Malik ibn ‘Umayr, from ‘Abdullah ibn al-Harith, from al-‘Abbas ibn ‘Abd al-Muttalib, that he said: O Messenger of Allah, your uncle Abu Talib used to protect you and benefit you. He said: "He is in a shallow part of the Fire, and were it not for me, he would have been in the lowest depth."