After this, in the month of Ṣafar of the twelfth year of the Hijra, the event known as the Battle of Mīzar took place. It is also called the Battle of Senī, named after a river.
Ibn Jarīr said: Regarding this event, people said: "The most precious of the months of Ṣafar! In this month, every tyrant was killed at the place where the rivers meet." The reason people said this was as follows: Hormuz had written a letter to Ardashīr and Shīrā, informing them that Khālid was coming towards them from Yamāma. Risra also sent Hormuz reinforcements under the command of Karīn b. Qaryānis. However, before these reinforcements reached Hormuz, Khālid fought with him, and Hormuz, along with some Persian soldiers, fled. Afterwards, the reinforcements under Karīn met up with Hormuz, they joined forces, and encouraged each other to fight Khālid again. They marched towards the region known as Mīzar. On the right and left flanks of the military unit under Karīn b. Qaryānis were again Kubāz and Anūshajān.
When Khālid learned of their approach, he set aside one-fifth of the spoils obtained from the expedition of Dhātu's-Salāsil and sent it with Walīd b. ʿUqba to Abū Bakr, informing him of the situation. Then he set out with his soldiers. Eventually, they reached the region of Mīzar and set up camp. He arrayed his troops. They fought fiercely for their ideals. Karīn came forth for single combat. Khālid b. al-Walīd stood before him. But Maqīl b. Aʿshā b. Nabāsh, one of the brave commanders who stepped forward, killed Karīn. ʿAdī b. Ḥātim killed Kubāz, and ʿĀṣim killed Anūshajān. The Persians fled, and the Muslims pursued them. That day, they killed 30,000 Persians. Many others drowned in the rivers and waters. Khālid remained in the region of Mīzar and took as booty the belongings of the slain Persians.
Karīn was a person of honor among the Persian people. Khālid gathered the remaining spoils and divided them into five parts. He sent one-fifth and the good news of victory to Abū Bakr al-Ṣiddīq. The person who brought the one-fifth share and the news of victory to Abū Bakr was Saʿīd b. Nuʿmān, the brother of the Banū ʿAdī b. Kaʿb. Khālid remained there for a while longer and distributed the remaining four-fifths of the booty among the soldiers. He took the women and children of the besieged warriors captive, but did not harm the farmers. He accepted their payment of jizya (poll tax). Among those taken captive were a Christian named Ḥabīb Abū Ḥasan al-Baṣrī, ʿUthmān's freedman Mafanna, and Muʿāghira b. Shuʿba's freedman Abū Ziyād.
Khālid b. al-Walīd entrusted command of the troops to Saʿīd b. Nuʿmān and the administration of the jizya to Suwayd b. Muqrin. He ordered Suwayd to go to the city of Ḥafīr and collect the goods. Khālid himself remained there to gather intelligence about the enemy.