This is a short scholarly introduction paired with a translated primary source: an 8th-century Friday sermon (khuṭba) delivered by Abū Ḥamza, a Khārijī rebel who briefly seized Mecca and Medina in 747 CE. The introduction surveys the Khārijī movement — an early and uncompromising Islamic faction that considered any Muslim who committed a major sin to be an apostate — focusing on the Ibāḍī sub-sect, the only branch to survive into the modern era, with communities in Algeria, Libya, Tunisia, Oman, and Zanzibar. The sermon itself is preserved in classical Arabic rhetorical collections as an exemplar of eloquence; Abū Ḥamza uses it to indict both the Umayyad caliphs (condemned individually by name for debauchery, tyranny, and misappropriating public funds) and the Shīʿī factions (dismissed as Qurʾān-ignorant soothsayer-followers awaiting a returning imām). A distinctive and historically striking feature is the sermon's canonical review of Islamic succession: it praises Abū Bakr and ʿUmar, faults ʿUthmān and ʿAlī as partial failures, and then unleashes sustained, sometimes scatological abuse on the Umayyads — making it a rare document in which Khārijī political theology is expressed in a preacher's own voice rather than through hostile sources. The text is of interest to readers in Islamic history, early Arabic rhetoric, and the history of Muslim sectarianism, offering both a scholarly frame and direct access to a moment of 8th-century religious polemic.