Al-Matalib al-'Aliyah 4250 — The Battle of Badr

It is narrated from Zayd bin Ali that he said: On the day of the Battle of Badr, the shi'ar (the special battle cry) of the Prophet (peace and blessings be upon him) was: 'Ya Mansur, amit' (O you who are granted Allah's help and victory, put (the enemy) to death!).
Its chain contains Muhammad bin Umar al-Waqidi, whom most hadith scholars have criticised and declared da'if (weak); however, words of this kind regarding battle cries are also reported in other books of sirah and hadith.