He appears in 627 during the siege of the Banu Qurayza, a Jewish tribe in conflict with Muhammad. The Qurayza had a long-standing alliance with the Aws and during the siege asked to confer with Abu Lubaba. According to Ibn Ishaq, Abu Lubaba felt pity for the women and children of the tribe who were crying and when asked whether the Qurayza should surrender to Muhammad, advised them to do so. However he also "made a sign with his hand toward his throat, indicating that [their fate] would be slaughter".
After Abu Lubaba had left, the Banu Qurayza unconditionally surrendered. Their men were subsequently killed, while their women and children were enslaved. Stillman infers from Abu Lubaba's gesture that Muhammad had decided the fate of the Qurayza even before their surrender.
Ibn Ishaq's account, going back to Abu Lubaba's own statements, related that he regreted his actions, stating: "My feet had not moved away from the spot before I knew I had been false to God and His Apostle". He then went to the mosque, tied himself to a pillar and declared: "I will not leave this place until God forgives me for what I have done". Muhammad declared that God had forgiven him after reportedly receiving a revelation.
- Stillman, Norman, The Jews of Arab Lands: A History and Source Book. Philadelphia: Jewish Publication Society of America, 1979. ISBN 0-8276-0198-0
- Guillaume, Alfred, The Life of Muhammad: A Translation of Ibn Ishaq's Sirat Rasul Allah. Oxford University Press, 1955. ISBN 0-1963-6033-1
- Peters, Francis E., Muhammad and the Origins of Islam. State University of New York Press, 1994. ISBN 0-7914-1875-8.
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