During Muslim conquest of Khuzestan, The highest commander of Muslim army, Abu Musa al-Ash'ari requested to the caliph to provide him with elite guards from Ansar (military) component, which replied by Umar to sent a group of Ansaris including al-Bara' ibn Malik along with his brother, Anas. In the campaign on Khuzestan, the Muslims faced a particularly difficult battle on the bridge of Susa, eastern of Tigris river, as the enemy gained upper hand at the first of the battle. Thus the Muslims soldiers once again came to al-Bara' asking for prayer, and after al-Bara' finished his prayer, the Muslims fight again until the managed to gained upper hand and seized victory.
