After the conquest of Makkah many pagan tribes had become Muslim voluntarily whereas there were others which accepted Islam when the Prophet sent his missionaries to them to instruct them into the doctrines and practices of the faith. One of his missionaries was Ali ibn Abi Talib. His master sent him to Yemen in 10 A.H. to invite the Yemeni tribes to Islam.
Though the last expedition that the Prophet organized was the one which was to be sent to the Syrian frontier under the command of Usama bin Zayd bin Haritha, it never left Medina in his lifetime. Therefore, the expedition of Ramadan of 10 A.H. which he sent to Yemen under the command of Ali, was the last one which actually left Medina while he was still alive.
Ali arrived in Yemen with his cavalry in mid-winter, and he invited the tribesmen of Madhhaj to accept Islam, but they answered him with a volley of arrows and rocks whereupon he also signaled his troops to charge. They attacked the tribesmen and routed them but did not pursue them because Ali's mission was one of peace and not of war. His orders to his troops were to fight only in self-defense.
The Madhhaj sued for peace which Ali readily granted them, and he renewed his invitation to them to accept Islam. This time they and also the tribe of Hamdan responded to his call, and accepted Islam. Ali's mission was successful. All Yemen became Muslim through his efforts. He executed his mission, as ever, with splendid competence and confidence, and demonstrated that he was the missionary of Islam par excellence.
The most powerful and influential group in Yemen was made up of the tribesmen of Hamdan. In late 8 A.H., the Apostle sent Khalid bin Walid to invite them to Islam. Khalid spent six months among them preaching Islam but could not win any converts, and his mission was a failure. He was a general and a conqueror but not a preacher and a missionary. At last the Apostle recalled him to Medina, and in his stead, sent Ali ibn Abi Talib.
Ali gathered the tribesmen of Hamdan in a plain, read before them the message of the Apostle of God, and presented Islam to them. This time they responded – by accepting Islam. The whole tribe became Muslim.
Ali sent a report on the outcome of his mission to the Apostle in Medina. When the latter read the report, he thanked God for His grace, and lifting his eyes toward Heaven, invoked blessings upon the tribe of Hamdan. This he did twice. (Sira-tun-Nabi, Vol. II, Tenth Edition, 1974, published by the Ma'arif Printing Press, Azamgarh, India).
During the last ten years of his life, the Prophet of Islam had organized eighty expeditions which left Medina on various missions – some warlike and others peaceful. Ali's expedition to Yemen is of especial interest because it was the last of them all. No other expedition left Medina in the lifetime of the Prophet.
The year 10 A.H. (A.D. 631) is called the Year of the Delegations. Many Arab tribes sent delegations to Medina both to accept Islam, and to give Muhammad Mustafa their pledge of allegiance as their temporal sovereign.
In year one of Hijri (A.D. 622) Medina had the status of a city-state but within ten years it had burgeoned into the capital of a “national” state. The whole peninsula had acknowledged its spiritual and temporal authority. Muhammad Mustafa, may God bless him and his house, had established internal peace in the whole country, and had taken effective steps to safeguard the “national” interests of the Muslim umma. There was no threat to the security of the Islamic State from any external aggression.
The Jews and the Christians were paying taxes or tribute (Jizya). They were enjoying all the rights of citizenship of the Islamic State, and they were enjoying full religious freedom. The Arabs, most of them now converted to Islam, were on the eve of a vigorous “national” renaissance. These were only a few of the countless blessings that Islam had brought to the Arabian peninsula.