Abu al-Bakhtari says that Sayyiduna Ali (may Allah be pleased with him) was asked: Were the people of the Camel polytheists? He said: They had fled from polytheism. It was asked: Were they hypocrites? He said: "They do not remember Allah except a little" [Surah al-Nisa: 142]; "The hypocrites remember Allah only a little." It was asked: Then who were they? He said: Our Muslim brothers who rebelled against us.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قتال أهل البغي / 16713