Ali bin Rabi'ah narrates: I heard Sayyiduna Ali (may Allah be pleased with him) say on this pulpit of yours: "The Prophet (peace and blessings be upon him) took a covenant from me that I would fight those who break (their pledge or covenant), those who turn away from the truth, and those who exit (from the religion)."
Abu Ya'la recorded it; its chain contains al-Rabi' bin Sahl, whom I do not know, and the rest of its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الخلافة / 8951