Kathir bin Namir narrates: I entered the mosque of Kufah on a Friday evening while Sayyiduna Ali (may Allah be pleased with him) was delivering a sermon to the people. Some people stood up in the corners of the mosque proclaiming (that judgment belongs to Allah alone). Sayyiduna Ali (may Allah be pleased with him) gestured with his hand like this and said: "A word of truth by which falsehood is intended. I await Allah's judgment concerning you. I will judge among you by the Book of Allah and the Sunnah of His Messenger, and I will distribute among you equally. We will not prevent you from praying in this mosque as long as your hands are with our hands, and we will not fight you until you fight us."
Al-Tabarani recorded it in al-Mu'jam al-Awsat. Its chain contains Muhammad bin Kathir al-Kufi, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب قتال أهل البغي / 10454