Battle of Hunayn
In the year 630, when the Muslim army conquered Mecca, Abu Ubaidah was commanding one of the four divisions that entered the city from four different routes. Later that year, he participated in the Battle of Hunayn and the Siege of Ta'if. He was also part of the Tabuk campaign under the command of Muhammad himself. On their return from the Battle of Tabuk, a Christian delegation from Najran arrived in Medina and showed interest in Islam and asked Muhammad to send them a person to guide them in the matters of religion and in other tribal affairs according to Islamic laws, Abu Ubaidah was appointed by Muhammad to go with them. He was also sent as the tax collector () to Bahrain by Muhammad. He was present in Mecca when Muhammad died in 632.