Abdullah ibn Umar
Heraclius was furious and then organized an army of 100,000 men. According to Al-Imam al-Waqidi, the first Muslim historian on the events, Abu Bakr then appointed Muawiyah's friend 'Amr ibn al-'As to lead the next band of 9000 men and they left for Palestine. Tom Holland in his book "The shadow of the sword, The Battle for Global Empire and the End of the Ancient World" writes: "With intense cunning the Arabs then launched a pincer movement against the Roman army. The second band then crossed the eastern frontier even as first one was in Gaza". When they arrived in Palestine Amr's say his friend Amir bin Adi returning from Palestine after visiting his family. Amir bin Adi told him there was a Roman Army 100,000 strong behind him that had been sent to confront him. 'Amr ibn al-'As then sent Abdullah ibn Umar with 1000 horsemen to gather intelligence on the Roman Army. They saw a Roman Reconnaissance of, according to Abdullah ibn Umar, 10,000 horsemen and took them on. Then returned to 'Amr ibn al-'As. Then 'Amr ibn al-'As with Abdullah ibn Umar took on another group.