While he was gaining followers for his rebellion, Ali adopted slogans of the egalitarian doctrine of the Kharijites, who "preached that the most qualified man should reign, even if he was an Abyssinian slave." He inscribed his banner and coins with Kharijite expressions and started off his Friday sermons with the slogan "God is great, God is great, there is no God but God, and God is great; there is no arbitration except by God," which was "the war cry used by the Kharijites when they defected from the ranks of Ali ibn Abi Talib during the battle of Siffin." At the same time, however, Ali did not completely abandon the pretense of being an Alid and maintained the claim that he was a Zaydi.