The Battle of al-Buwayb, in which the Muslims exacted retribution from the Persians

When the Persian commanders heard of this, and of the growing strength of al-Muthannā’s forces, they dispatched another army against him under a man called Mihrān. The two armies converged at a place named al-Buwayb (1), near the site of present-day Kūfah, with the Euphrates lying between them.

The Persians said, “Either you cross over to us, or we will cross over to you.”
The Muslims replied, “No—cross over to us.”
So the Persians forded the river and the two sides drew up in Ramadan. Al-Muthannā then ordered the Muslims to break their fast, and they all did so to strengthen themselves. The army was deployed, and he walked past every banner borne by the tribal commanders, admonishing them and urging them to strive in jihad, to be patient, and to keep silent.

Among the fighters were Jarīr ibn ʿAbd Allah al-Bajalī with the whole of Bajīlah, and a number of other leading Muslims.

Al-Muthannā told them, “I shall pronounce the takbīr three times; prepare yourselves. When I give the fourth takbīr, charge.” They received his command with ready obedience.

Yet when he gave the first takbīr the Persians struck first, advancing until they closed with the Muslims, and a fierce battle began. Al-Muthannā noticed a breach in one of his ranks, so he sent a messenger to say, “The commander sends you his salām and says: Do not disgrace the Arabs today—close your ranks.” When he saw them— they were Banū ʿIjl—comply, he was pleased and laughed.

He then sent word: “People of Islam, fight in your accustomed manner; support Allah and He will support you.” Al-Muthannā and the Muslims kept beseeching Allah for triumph and victory.

When the fighting dragged on, al-Muthannā gathered a band of his champion companions to guard his back, then charged at Mihrān, driving him from his position and forcing his way into the enemy’s right wing. A young Christian from Banū Taghlib then charged and killed Mihrān, mounting his horse—so reports Saif ibn ʿUmar (3).

Muhammad ibn Isḥāq, however, states that al-Mundhir ibn Ḥassān ibn Ḍirār al-Ḍabbī was the one who charged him and pierced him, while Jarīr ibn ʿAbd Allah al-Bajalī cut off his head. The two disputed over his spoils (4): Jarīr took his weapons, and al-Mundhir his belt.

The Magians fled, and the Muslims pressed upon their backs, cutting them down. Al-Muthannā ibn Ḥārithah hastened to the bridge and stood on it, preventing the Persians from crossing and enabling the Muslims to finish them off. The pursuit lasted the rest of that day and through the night, even into the late hours. It is said that on that day nearly one hundred thousand of them were killed or drowned—praise and bounty belong to Allah.

The Muslims captured vast wealth and plentiful provisions, and they sent the glad tidings and the one-fifth share to ʿUmar (may Allah be pleased with him). Many eminent Muslims also fell that day.

This battle humbled the Persians, and the Companions were able to raid their lands between the Euphrates and the Tigris, acquiring booty so great it cannot be counted. And further encounters then followed