Sayyiduna Sinan bin Wabrah (may Allah be pleased with him) narrates: On the occasion of the Battle of al-Muraysi', that is, the Battle of Banu al-Mustaliq, we were with the Prophet (peace and blessings be upon him), and their battle cry was: "O Mansur! Give death, give death!" (or: Kill!)
Al-Tabarani recorded it in al-Mu'jam al-Awsat and al-Mu'jam al-Kabir, and the chain of al-Mu'jam al-Kabir is hasan (good).