Musannaf Ibn Abi Shaybah

Hazrat Abdullah bin Amr (may Allah be pleased with him) narrates that when, at Siffin, people raised their hands for attack, Hazrat Amr bin Aas recited these verses: The battle has intensified, I have prepared a brave and high-bred horse for this fight. He meets hardship with hardship, and when horsemen draw near to each other, he becomes even stronger. He is swift and large, and when he is drenched with water, he becomes even more agile. After this, Hazrat Abdullah bin Amr (may Allah be pleased with him) recited verses: If the young men of Siffin were to see me standing, their hair would turn white. It was that night when the people of Iraq came like clouds. At that time, our ranks were surging like the waves of the sea. Their mill turned and our mill turned, and our shoulders pressed together. When I would say that they had fled, a group of them would suddenly come and attack. They would say to us, pledge allegiance at the hand of Hazrat Ali (may Allah be pleased with him), and we would say, you fight.