The Farewell Pilgrimage
In that year, the Messenger of Allah [peace and blessings be upon him and his Progeny] ordered to his close followers to call all the people in different places to join him in his last pilgrimage. On this pilgrimage he taught them how to perform the pilgrimage in a correct and unified form.
This was first time that the Muslims with this magnitude gathered in one place in the presence of their leader, the Messenger of Allah (PBUH). On his way to Makkah, more than seventy thousand people followed the Prophet (PBUH). On the fourth day of Dhu'l-Hijjah more than one hundred thousand Muslims had entered Makkah.
After completing his last pilgrimage (Hajjatul-Wada'), the Prophet (PBUH) was leaving Makkah toward Madinah, where he and the crowd of people reached a place called Ghadir Khumm (which is close to today's al-Juhfah). It was a place where people from different provinces used to greet each other before taking different routes for their homes.
In this place, the following verse of the Quran was revealed:
"O Apostle! Deliver what has been sent down to you from your Lord; and if you don't do it, you have not delivered His message (at all); and Allah will protect you from the people ..." (Quran 5:67)
The last sentence in the above verse indicates that the Prophet (PBUH) was mindful of the reaction of his people in delivering that message but Allah informs him not to worry, for He will protect His Messenger from people.
Upon receiving the verse, the Prophet (PBUH) stopped on that place (the pond of Khumm) which was extremely hot. Then he sent for all people who have been ahead in the way, to come back and waited until all pilgrims who fell behind, arrived and gathered. He ordered Salman (RA) to use rocks and camel toolings to make a pulpit (minbar) so he could make his announcement. It was around noon time in the first of the Fall, and due to the extreme heat in that valley, people were wrapping their robes around their feet and legs, and were sitting around the pulpit, on the hot rocks.
On this day the Messenger of Allah(PBUH) spent approximately five hours in this place; three hours of which he was on the pulpit. He recited nearly one hundred verses from The Glorious Quran, and for seventy three times reminded and warned people of their deeds and future. Then he gave them a long speech.
The following is a part of his speech which has been widely narrated by the Sunni traditionists (Hadith narrators):
Tradition (Hadith) of the Two Weighty Things (Thaqalayn)
The Messenger of Allah (PBUH) declared:
"It seems the time approached when I shall be called away (by Allah) and I shall answer that call. I am leaving for you two precious things and if you adhere to them both, you will never go astray after me. They are the Book of Allah and my Progeny, that is my Ahlul Bayt. The two shall never separate from each other until they come to me by the Pool (of Kawthar in Paradise)."
Then the Messenger of Allah continued:
"Do I not have more right over the believers than what they have over themselves?"
People cried and answered: "Yes, O' Messenger of God."
Then followed the key sentence denoting the clear designation of Ali (AS) as the leader of the Muslim Ummah. The Prophet (PBUH) held up the hand of Ali (AS) and said:
"For whoever I am his Leader (mawla), Ali is his Leader (mawla)." [In some narrations the word used was wali rather than mawla - with the same implication]
The Prophet (PBUH)continued:
"O' God, love those who love him, and be hostile to those who are hostile to him."
These were the key parts of the speech of the Prophet (PBUH). There are also more detailed versions of this sermon which are recorded by many Sunni authorities.
Immediately after the Prophet (PBUH) finished his speech, the following verse of the Quran was revealed:
"Today I have perfected your religion and completed my favour upon you, and I was satisfied that Islam be your religion." (Quran 5:3)
The above verse clearly indicates that Islam without clearing up matter of leadership after Prophet (PBUH) was not complete, and completion of religion was due to announcement of the Prophet's (PBUH) immediate successor.
Immediately after the Prophet's (PBUH) speech, Hassan bin Thabit, the Companion and poet of the Messenger of Allah, asked for his permission to compose a few verses of poetry about Imam Ali (AS) for the audience. The Prophet (PBUH) said: "Say with the blessings of Allah". Hassan stood up and said: "O' people of Quraysh. I follow with my words what preceded and witnessed by the Messenger of Allah [PBUH]. He then composed the following verses at the scene:
He calls them, (on) the day of Ghadir, their Prophet
In Khumm so hear (and heed) the Messenger's call,
He said: "Who is your guide and leader? (mawlakum wa waliyyukum)"
They said, and there was no apparent blindness (clearly):
"Your God, our guide, and you are our leader
And you won't find from among us, in this, any disobedient,"
He said to him: "Stand up O' Ali, for I am
pleased to announce you Imam and guide after me (min ba'di imam(an) wa hadiy(an)),
So whomever I was his leader (mawla), then this is his leader (mawla)
So be to him supporters in truth and followers,"
There he prayed: "Allah! Be a friend and guide to his follower
And be, to the one who is Ali's enemy, an enemy"
Oath of Allegiance
After his speech, the Messenger of Allah (PBUH) asked everybody to give the oath of allegiance to Ali (AS) and congratulate him and they did.
Allah ordered His Prophet (PBUH) to inform the people of this designation at a time of crowded populous so that all could become the narrators of the tradition, while they exceeded a hundred thousand.