Dailami, Firduas Al-Akhbar, V.3, page 542, hadith 5689; Manawi, Faiz al-Qadir, V.6, page 190; Ahmad ibn Hanbal, Musnad, V.6, page 323; Hakim Naishaburi, Al-Mustadrak, V.3, page 121; Haithami, Majma’e al-Zavaed, V.9, page 130; Suyuti, Al-Jami' as-Saghir, V.2, page 608; Muttaki Hindi, Kanz al-Ummal, V.11, page 602; Kharazmi in his book Al-Manaqib (136-137) narrates from Saeed ibn Jubair as saying: "Ibn Abbas was notified about a group engaged in slandering Ali. He said to his son (Ali ibn Abdullah), "Catch hold of my hand and take me to that group." His son obeyed. When he reached them, he said, "Which one of you was insulting Allah?" Everyone responded with surprise: "Subhan Allah! The one who defames Allah is a polytheist.

So he asked, "Who among you was defaming the Messenger of Allah (s.a.w.a.)? Again, they said, "What are these words? The one who defames the Messenger of Allah (s.a.w.a.) is an infidel.

Then he said, "Which of you defamed Ali?"

They said, "We had defamed him."

Ibn Abbas said, "Be witness that I heard the holy Prophet (s.a.w.a.) say, "Whoever defames Ali has defamed me, and whoever defames me has defamed Allah, and whoever defames Allah, then Allah will cast him with face into the Fire." Muhibuddin Tabari has narrated this matter in Riyazh al-Nazhra (V.3, p.122-123).