This battle – in Iraq – is considered to be an equivalent of Al-Yarmuk in the Levant; the Persian princes mobilized the troops under leadership of Mahran to meet the Muslims who were led by Al-Muthanna Ibn Harithah. Both armies gathered in a place called Al-Buwayb –near today Koufa- where Euphrates River laid between the two groups. They suggested that one of the two groups should cross the river and the Muslims said that the Persians were to do that; and so did they meet (after meeting, did the fighting ensue or not?) one another in Ramadan.
Al-Muthanna pushed the Muslims not to fast, in order to find enough power to face their enemies and then he mobilized his army and went to each and every brigade –amongst which was Abdullah Al-Bajaly leading Bajila and a number of Muslim leaders. Muthanna advised and encouraged them to strive, be patient and stick to silence.
He also told them that he’d give four loud Takbir (chanting Allah Akbar) and that they should get set during the first three ones and launch their attack at hearing the fourth, which was received by all of them with complete obedience.
However, when Al-Muthanna started the first Takbir, the Persians quickly launched an attack and the Muslims strongly faced them until they besieged them, and they had a furious fight, during which both sides exerted desperate effort.
Al-Muthanna then found a fissure in a side of his troops, so he sent a man to them telling them to do their best not to cause ruin for the Arabs so they quickly fixed their lines! Watching them Al-Muthanna was impressed with what he saw, so he laughed and sent them another message telling them to fight for the sake of Allah in order to gain His support.
Al-Muthanna and the Muslims then prayed a lot to Allah asking him to grant them victory, but when the fight went longer and longer without any sign of change Al-Muthanna gathered a number of his best fellows to cover him and he launched a strong attack on Mahran himself and finally pushed him off his place, until he reached the right wing of the Persian army.
Muhammed Ibn Is-haq, describing this, said that Al-Mundhir Ibn Hassaan Ibn Dirar Ad-Dabbi then attacked the Persian leader and stabbed him while Jarir Ibn `Abdullah Al-Bajaly cut off his head.
Seeing this, the Persians started to escape and the Muslims followed them; cutting off their heads. Al-Muthanna also went quickly to the bridge to prevent the Persians from crossing back, to enable Muslims to get them. Muslims chased them for the rest of the day and even after dark had fallen.
It was said that that around 100, 000 were killed, and – thanks to Allah Almighty – Muslims captured much food and money that day and sent to `Umar Ibn Al-Khattab breaking the good news to him and presenting him the one-fifth of the booty.
And although a large number of Muslims leaders were also killed, this battle forced the Persians to surrender to Muslims, enabling the Companions –may Allah be pleased with them all- to launch other attacks between the two rivers; Tigris and Euphrates gaining a tremendous fortune.