The first Amir-ul-Haj.
In 631 C.E., the Holy Prophet sent from Madina a delegation of three hundred Muslims to perform the Haj according to the new Islamic way. Abu Bakr was appointed as the leader of the delegates. Abu Bakr had thus the honor of being the first Amir-ul-Haj in the history of Islam.
Some time after Abu Bakr and his party had left for the Haj, the Holy Prophet received revelation about the regulation of the Haj, and the ordering of relationship with the infidels. It is related that when the revelation came, some one suggested to the Holy Prophet that he should send news of it to Abu Bakr. The Holy Prophet said that a man of his own house was to proclaim the revelation. The Holy Prophet summoned Ali, and commissioned him to proclaim the revealed verses to the people on the day of sacrifice when they were assembled at Mina. Ali went forth on the Holy Prophet’s slit-eared camel, and overtook Abu Bakr and his party. When Ali joined the party, Abu Bakr wanted to know whether he had come to give orders or to convey them. Ali said that he had not come to replace Abu Bakr as Amir-ul-Haj, and that his only mission was to convey a special message to the people on behalf of the Holy Prophet.
At Makkah, Abu Bakr presided at the Haj ceremony, and Ali read the proclamation on behalf of the Holy Prophet. The main points of the proclamation were: Henceforward the non-Muslims were not to be allowed to visit the Ka’aba or perform the pilgrimage. No one was to be allowed to circumambulate the Ka’aba naked. Polytheism was not to be tolerated. Where the Muslims had any agreements with the polytheists such agreements were to be honored for the stipulated periods. Where there were no agreements, a grace period of four months was to be given, and thereafter no quarter was to be given to the polytheists.
The new era.
From the day this proclamation was made a new era dawned in Arabia. Henceforward Islam alone was to be supreme in Arabia. In some quarters an argument is advanced that as On this occasion the proclamation was read by Ali on behalf of the Holy Prophet that established the precedence of Ali over Abu Bakr, and that therefore when after the death of the Holy Prophet, Abu Bakr became the Caliph in disregard of the claims of Ali, he was a usurper. It will be seen that on this occasion Ali did not replace Abu Bakr as Amir-ul-Haj.
Ali was merely assigned a special mission to read the proclamation as according to the Holy Prophet only a man from his own house had to communicate the revelation. We can thus say that on that occasion Abu Bakr represented the temporal side while Ali represented the spiritual side. After the death of the Holy Prophet there was no longer the question of any spiritual representation; the issue was only temporal representation, and for this Abu Bakr was the best choice as he had represented the Holy Prophet even in his life-time.