Ka'b ibn Asad al-Qurazi

Kaʿb ibn Asad al-Quraẓī was the chieftain of Banū Qurayẓah, the last of the three Jewish tribes of Madinah remaining under treaty with the Muslims after the expulsions of Banū Qaynuqāʿ and Banū Naḍīr. During the Battle of the Trench (5 AH), Huyayy ibn Akhṭab, the exiled chieftain of Banū Naḍīr, snuck into Madinah and pressed Kaʿb, over repeated visits, to break Qurayẓah's treaty with the Muslims and join the Confederate siege. Kaʿb initially refused three times, citing the honor of the treaty, but eventually relented under Huyayy's persistent promises of protection and a share of the coming victory. When the Prophet ﷺ, alerted to the danger, sent al-Zubayr ibn al-ʿAwwām to investigate and then a delegation of four Anṣārī leaders who had old ties to Qurayẓah from the pre-Islamic era to confirm the treaty directly, Kaʿb gave only evasive answers and, by one report, physically tore up the written treaty rather than honor it. When Saʿd ibn Muʿādh and Saʿd ibn ʿUbādah were later sent to confirm the betrayal outright, Kaʿb denied any treaty had ever existed, and when one of the Saʿds began cursing him in anger, retorted that the matter between them was now "beyond just cursing." His betrayal, striking at the exact moment the Muslims were besieged from without by the Confederates, brought Madinah to what several Companions described as its most terrifying night of the entire Sirah.