Musnad Ahmad 5:197

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Ishaq, who said: I heard Najiyah ibn Ka‘b narrating from ‘Ali, that he came to the Prophet, may Allah bless him and grant him peace, and said: "Abu Talib has died." The Prophet, may Allah bless him and grant him peace, said to him: "Go and bury him." He said: "He died as a polytheist." He said: "Go and bury him." He said: So when I had buried him, I returned to the Prophet, may Allah bless him and grant him peace, and he said to me: "Perform ghusl (ritual washing)."