The Ninth Year of Hijrah
The ninth year of the hijrah is known as the Year of Embassies, as being the year in which the various tribes of Arabia submitted to the claim of the Prophet and sent embassies to render homage to him.
These tribes had been awaiting the issue of the war between Muhammad and the Quraish; but as soon as that tribe - the principal of the whole nation and the descendants of Ishmael, whose prerogatives none offered to dispute - had submitted, they were satisfied that it was not in their power to oppose Muhammad. Hence their embassies flocked into Medina to make their submission to him. The conquest of Mecca decided the fate of idolatry in Arabia. Now deputations began to arrive from all sides to render the adherence to Islam of various tribes. Among the rest, five princes of the tribe of Himyar professed Islam and sent ambassadors to notify Muhammad of the same. These were the princes of Yemen, Mahra, Oman, and Yamama.
The Tenth Year of Hijrah
During the tenth year of the hijrah, as in the preceding one, numerous embassies continued to pour into Medina from all parts of Arabia, to testify to the allegiance of their chiefs and their tribes. Teachers were sent by the Prophet into the different provinces to teach the new converts the principles and precepts of Islam. These teachers were invariably given the following injunctions when they were about to depart on their mission: "Deal gently with the people, and be not harsh; cheer them, and do not look down upon them with contempt. You will meet with many believers in the Holy Scriptures, who will ask you: 'What is the key to heaven?' Answer them that it (the key to heaven) is to bear witness to the divine truth and to do good."
The Eleventh Year of Hijrah
The eleventh year of the hijrah, being the last year of Muhammed's life, was spent at Medina. There he settled the organization of the provincial and tribal communities which had adopted Islam and become the component parts of the Muslim federation. More officers had to be deputed to the interior provinces for the purpose of teaching their inhabitants the precepts of the religion, administering justice, and collecting zakat. Muadh Ibn Jabal was sent to Yemen. On his departure to that distant province the Prophet enjoined him to use his own discretion in the event of his being unable to find express authority in the Qur'an. Ali was deputed to Yamama in the southeast of the peninsula. To him the Prophet said: "Never decide between any two parties who come to you for justice unless you first hear both of them."