During the early developing stages of the Islamic state, the Quraysh group had yet to crystallize. It was not until the departure of the Holy Prophet that the group fully emerged onto the scene. Two factors hastened its assembly and emergence: the first was the news of the Prophet’s impending death; and second was the Prophet’s repeated orders that Ali b. Abi Talib was to succeed him in leading the Muslim ummah.
In the tenth year of the Hijrah (632 CE), the day came when the Prophet stunned the ummah by indicating that he would soon leave the world while returning from his first and last pilgrimage, forever known as the “Farewell Pilgrimage.” Surrounded by over 100,000 hujjaj (pilgrims) in the blazing heat, near the oasis pond of Ghadir Khum, the Prophet was intercepted with a revelation that forced him to stop the pilgrims in their track to hear a new revelation from Allah. The revelation was as follows:
O Messenger! Convey what had been revealed to you from your Lord; if you do not do so, then [it would be as if] you have not conveyed His message [at all]. Allah will protect you from the people. (c. 5:67)
After revealing this verse, the Prophet then gave his famous last sermon known as Khutbatul Widah (The Farewell Sermon).
After praising God, the Prophet openly spoke to the pilgrims that the Angel Gabriel had reviewed the Holy Qur’an with him twice that year instead of once, and this was a sign that his time of death was near.
Then the critical question was at hand, the Prophet asked the pilgrims if he had more authority (wilayah) over the believers than they had over themselves, to which they all replied, “yes.” Then the Prophet raised the hand of Ali b. Abi Talib and said, “Whosoever’s master (mawla) I am, this Ali is also his master (man kuntu mawlahu fa hadha Aliyun mawlahu).” The order was sealed and Ali b. Abi Talib became the Prophet’s successor by Divine order. At this point, the Prophet publicly took the oaths from those present, including Abu Bakr, Umar b. al-Khattab, Ammar b. Yasir, Abu Dharr al-Ghifari, Salman al-Farsi, al- Miqdaad b. al-Aswad, and Abdullah b. al-Abbas. Some even approached Ali to congratulate him personally, like Umar b. al-Khattab, who said, “Congratulations Ibn Abi Talib! Today you became the leader (mawla) of all believing men and women.”
An excerpt of the Prophet’s farewell sermon:
It is probable that I will be called soon and I will respond. So I leave behind me among you two weighty [very worthy and important] things: the Book of Allah, which is a rope stretched between the heavens and the Earth; and my progeny [Ahlul Bayt]. For verily Allah, the Merciful, the Aware informed me that these two would never become separated from each other until they meet at the Fount of Abundance. Therefore, be careful how you will treat these two in my absence.
This was not the first time that the Holy Prophet had named Ali b. Abi Talib as his successor (aside from referring to the designated members of his Ahlul Bayt that were to succeed him) on numerous occasions, such as in the “Feast of the Clan” (al-Indhar). Moreover, portions of the Holy Qur’an refer to Ali b. Talib’s successionship.
 Successorship (khalifah or imamah) according to both schools of thought, Ahlul Bayt and Companions, is the representation of Prophet Muhammad, in the affairs of deen (faith) and duniyah (life).
 Ghadir Khum (which is close to today’s al-Juhfah in the Arabian Peninsula). It was the center point where routes from different provinces met and then parted to go their separate ways.
 Al-Tabari, Tarikh al-Tabari, 2:435
 Ahmad b. Hanbal, Musnad Ahmad, 4:281; Sirr al-Alamin; Al-Tabari, Al-Riyadh al-Nadhirah, 2:169
 Ahmad b. Hanbal, Musnad Ahmad 4:81, Ibn Abu Yallah al-Musilli, Musnad; Abu Bakr b. Abi Shibah, Al-Musnaf; Abu Bakr al-Baghdadi; Sirr al-Alamin, Abu Hamid al-Ghazali; Al-Milal wal-Nihal, Abu al-Fattah al-Shahrestani; Al-Bidayah wa al-Nihaya, 5:209; Ibn Katheeral-Shami; Al-Sawaeq al-Muhriqah, Ibn Hajar al-Askalani, p.26; Tafseer al-Tabari, 3:310; Muhammad b. Jarrer, Allamah Amini in Al-Ghadeer, 1:283, has compiled over sixty prominent Sunni sources that narrated the congratulations of Abu Bakr and Umar to Imam Ali on his succession by the Prophet on the Day of Ghadir.
 See Holy Qur’an, 108:1-3
 “Feast of the Clan,” after the revelation of c. 26:214 (“And warn thy nearest relations”), the Prophet made a feast and invited his extended family, so he could announce his prophethood and invite them to embrace his message. It was also the same event, in which the Prophet first declared that Ali b. Abi Talib would be his successor and caliph after him.
 See Holy Qur’an, 5:55 and 4:59