Abu Musa Abd Allah ibn Qays al-Ash'ari, better known as Abu Musa al-Ash'ari (Arabic: أبو موسى الأشعري) (d. ca. 662 or 672) was a companion of Muhammad and an important figure in early Islamic history. He was at various times governor of Basra and Kufa and was involved in the early Muslim conquest of Persia.
Abu Musa came originally from Zabid, region of Yemen, where his tribe, the Ashar, lived in the pre-Islamic period. He accepted Islam at Mecca prior to the hijra and returned to his native Yemen to propagate the faith. There was no news of him for more than a decade until following the conquest of Khaybar in 628 when he came to Muhammad in Medina with more than fifty converts from Yemen including his two brothers Abu Ruhm and Abu Burdah.
Following the conquest of Mecca in 629, Abu Musa was named among those sent by Muhammad on the expedition to Awtas. Two years later he was appointed as one of the governors over Yemen, where he remained until the caliphate of Abu Bakr, whom he joined in fighting the local leader of the ridda (lit. apostasy) movement.
He was present during the Expedition of Dhat al-Riqa. Some scholars claim, the expedition took place in Nejd (a large area of tableland in the Arabian Peninsula) in Rabi‘ Ath-Thani or Jumada Al-Ula, 4 A.H (or beginning of 5AH). They substantiate their claim by saying that it was strategically necessary to carry out this campaign in order to quell the rebellious bedouins in order to meet the exigencies of the agreed upon encounter with the polytheists, i.e. minor Badr Battle in Sha‘ban, 4 A.H. Muhammed received the news that certain tribes of Banu Ghatafan were assembling at Dhat al-Riqa with suspicious purposes.
Muhammad proceeded towards Nejd at the head of 400 or 700 men, after he had mandated Abu Dhar - in the Ummayad version, the Ummayad chief who killed Abu Dhar is given this honor: Uthman bin Affan - to dispose the affairs of Madinah during his absence. The Muslim fighters penetrated deep into their land until they reached a spot called Nakhlah where they came across some bedouins of Ghatfan.