In the various works of Shaykh al-Islām Ibn Taymiyyah (728H) is a very insightful, detailed and elaborate analysis of the Khārijite doctrine and the underlying reasons for its appearance. From the foundational errors of the Khārijites is that they make error (khaṭāʾ) bound to sinfulness (ithm), and from that point they are led in the direction of takfīr.

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