Abu Bahr Al-Ahnaf ibn Qays (الأحنف بن قيس) was a Muslim commander who lived during the time of Islamic prophet Muhammad. He hailed from the Arab tribe of Banu Tamim and was born of noble parents. Initially, his father named him ad-Dhahhak, but people called him al-Ahnaf, which meant "the clubfooted" in classical Arabic. Al-Baladhuri, however, noted that he was also identified as Abdallah ibn Khazim.
In the early years of Islam, Muhammad sent a missionary to the tribe of Banu Tamim. The tribe members had informed the missionary that no decision could be taken until Al-Ahnaf told them his opinion. Al-Ahnaf listened and questioned the missionary who succeeded in persuading him and his entire tribe to embrace Islam.
Al-Ahnaf had never met Muhammad in his lifetime. After Muhammad's death in 632, a number of tribes rebelled for different reasons, al-Ahnaf and his people, however, remained Muslims. When he heard about Musaylimah's claim of prophecy, al-Ahnaf went with his uncle to meet him. After listening to Musaylimah, he returned to his tribe and discouraged them from believing to Musaylimah's claim.
When Umar ibn al-Khattab became caliph in 634, the Muslim conquests outside the Arabian Peninsula increased, and Al-Ahnaf encouraged his people to participate. When Persians surrounded a Muslim division led by al-'Alaa ibn al-Hadrami, in Iraq, Umar ordered Utbah ibn Ghazwan to go to their rescue. Utbah sent a force of 12,000, most of them form the Banu Tamim, and among them was al-Ahnaf who played a major role in breaking the siege.
In 639, al-Ahnaf returned to Medina bringing news of the conquest of Tustar, and informing Umar of affairs in Persia. After listening to him, Umar said;
Maybe the Persians breach the treaties so often because the Muslims mistreat them?
Al-Ahnaf replied:
You have forbidden us to pursue any further conquest, and the Persian emperor is now in safety among his people. They will continue to be at war with us as long as he is commanding them to do so... unless you allow us to pursue further into the conquest.