Musannaf Ibn Abi Shaybah 35822 — Battle cries

Al-Zubayr bin Surakh said: Mus'ab bin al-Zubayr said to us, while we were lined up facing al-Mukhtar, "Your battle cry should be 'Ha Mim, la yunsarun' (Ha Mim, they will not be helped), for this was also the battle cry of the Prophet (peace and blessings be upon him)."