Bismillahir Rahmanir Raheem.
18th Zilhijja of 10AH event of Ghadir al Khum, where the Messenger of Allah (swt) delivered his LAST sermon. The greatest parallel/frequent (Mutawatir) tradition in the History of Islam is related to this sermon of the Prophet (s). More information can be found on internet
http://www.al-islam.org/encyclopedia/chapter3/2.htmlf for a complete list of 110 companions of Prophet (s) who narrated this tradition, as well as classified lists of the Sunni traditionists/historians/commentators of Quran who confirmed this tradition to be authentic and frequent, and their corresponding books where the tradition can be found.
The Farewell Pilgrimage
Ten years after the migration, the Messenger of Allah 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.
On his way to Mecca, more than seventy thousand people followed Prophet (s). On the fourth day of Zilhaj, more than one hundred thousand Muslims had entered Mecca. Revelation of Verse 5:67 On the 18th of Zilhaj, after completing his last pilgrimage (Hajjatul-Widaa), Prophet (s) was leaving Mecca toward Medina, where he and the crowd of people reached to a place called Ghadir Khum (which is close to today's Juhfah). It was a place where people from different provinces should say Good bye to each other and take different routes for their home.
In this place, the following verse was revealed: "O Muhammad! Deliver what has been sent down to you from your Lord; and if you don't do it, then, (it will be as if) you have not delivered His message (at all); and surely Allah will protect you from (the mischief) of men; verily, Allah does not guide a disbelieving people." (Quran 5:67).
Some of Sunni references confirming that the revelation of the above verse of Quran was right before the speech of Prophet in Ghadir Khum:
a.. Tafsir al-Kabir, by Fakhr al-Razi, under commentary of verse 5:67, v12, pp 49-50, narrated on the authorities of Ibn Abbas, al-Bara Ibn Azib, and Muhammad Ibn Ali.
b.. Asbab al-Nuzool, by al-Wahidi p50, narrated on the authorities of Atiyyah and Abu Sa'id al Khudri.
c.. Nuzul al-Quran, by al-Hafiz Abu Nu'aym narrated on the authorities Abu Sa'id Khudri and Abu Rafi.
d.. al-Fusool al Muhimmah, by Ibn Sabbagh al-Maliki al-Makki, p24
e.. Durr al-Manthur, by al-Hafiz al-Suyuti, under commentary of verse 5:67
f.. Fathul Qadir, by al-Shawkani, under commentary of verse 5:67
g.. Fathul Bayan, by Hasan Khan, under commentary of verse 5:67
h.. Shaykh Muhi al-Din al-Nawawi, under commentary of verse 5:67
i.. al-Sirah al-Halabiyah, by Noor al-Din al-Halabi, v3, p301
j.. Umdatul Qari fi Sharh Sahih al-Bukhari, by al-Ayni
k.. Tafsir al-Nisaboori, v6, p194
l.. and many more such as Ibn Mardawayh, etc...
The last sentence in the above verse indicates that the Prophet (s) 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.
The Speech
Upon receiving the verse, the Prophet (s) stopped on that place (the pond of Khum) which was extremely hot. Then he sent for all people who were 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 that he could make his announcement.
It was around noon time and due to the extreme heat, 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 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 long speech. The following is a part of his speech which has been widely narrated by the Sunni traditionists: The Messenger of Allah 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 both of them, 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 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 Allah." Then Prophet (s) held up the hand of Ali and said: "Whoever I am his leader (Mawla), Ali (`a) is his leader (Mawla). O' Allah, love those who love him, and be hostile to those who are hostile to him."
Some of the Sunni references:
a.. Sahih Tirmidhi, v2, p298, v5, p63
b.. Sunan Ibn Maja, v1, pp 12,43
c.. Khasa'is, by al-Nisa'i, pp 4,21
d.. al-Mustadrak, by al-Hakim, v2, p129, v3, pp 109-110,116,371
e.. Musnad Ahmad Ibn Hanbal, v1, pp 84,118,119,152,330, v4, pp 281,368,370, 372,378, v5, pp 35,347,358,361,366,419 (from 40 chains of narrators)
f.. Fada'il al-Sahaba, by Ahmad Hanbal, v2, pp 563,572
g.. Majma' al-Zawa'id, by al-Haythami, v9, p103 (from several transmitters)
h.. Tafsir al-Kabir, by Fakhr al-Razi, v12, pp 49-50
i.. Tafsir al-Durr al-Manthur, by al-Hafiz Jalaluddin al-Suyuti, v3, p19
j.. Tarikh al-Khulafa, by al-Suyuti, pp 169,173
k.. al-Bidayah wal-Nihayah, by Ibn Kathir, v3, p213, v5, p208
l.. Usdul Ghabah, by Ibn Athir, v4, p114
m.. Mushkil al-Athar, by al-Tahawi, v2, pp 307-308
n.. Habib al-Siyar, by Mir Khand, v1, part 3, p144
o.. Sawaiq al-Muhriqah, by Ibn Hajar al-Haythami, p26
p.. al-Isabah, by Ibn Hajar al-Asqalani, v2, p509; v1, part1, p319, v2, part1, p57, v3, part1, p29, v4, part 1, pp 14,16,143
q.. Tabarani, who narrated from companions such as Ibn Umar, Malik Ibn al-Hawirath, Habashi Ibn Junadah, Jari, Sa'd Ibn Abi Waqqas, Anas Ibn Malik, Ibn Abbas, Amarah,Buraydah,...
r.. Tarikh, by al-Khatib Baghdadi, v8, p290
s.. Hilyatul Awliya', by al-Hafiz Abu Nu'aym, v4, p23, v5, pp26-27
t.. al-Istiab, by Ibn Abd al-Barr, Chapter of word "ayn" (Ali), v2, p462
u.. Kanzul Ummal, by al-Muttaqi al-Hindi, v6, pp 154,397
v.. al-Mirqat, v5, p568(23) al-Riyad al-Nadirah, by al-Muhib al-Tabari, v2, p172
w.. Dhaka'ir al-Uqba, by al-Muhib al-Tabari, p68
x.. Faydh al-Qadir, by al-Manawi, v6, p217
y.. Yanabi' al-Mawaddah, by al-Qudoozi al-Hanafi, p297
Revelation of Verse 5:3 Immediately after the Prophet (s) finished his speech, the following verse of Holy Quran was revealed: "This day I have perfected for you your religion, and have completed my favour on you, and have chosen for you Islam (as your) religion." (Quran 5:3)
Some of Sunni references which mentioned the revelation of the above verse of Quran in Ghadir Khum after the speech of the Prophet (s) :
a.. al-Durr al-Manthur, by al-Hafiz Jalaluddin al-Suyuti, v3, p19
b.. Tarikh, by Khatib al-Baghdadi, v8, pp 290,596 from Abu Hurayra
c.. Manaqaib, by Ibn Maghazali, p19
d.. History of Damascus, Ibn Asakir, v2, p75
e.. al-Itqan, by al-Suyuti, v1, p13
f.. Manaqib, by Khawarazmi al-Hanfi, p80
g.. al-Bidayah wal-Nihayah, by Ibn Kathir, v3, p213
h.. Yanabi' al-Mawaddah, by al-Qudoozi al-Hanafi, p115
i.. Nuzul al-Quran, by al-Hafiz Abu Nu'aym narrated on the authority Abu Sa'id Khudri.... and more.
The above verse clearly indicates that Islam without clearing up matter of leadership after Prophet (s) was not complete, and completion of religion was due to announcement of Prophet's immediate successor.
Oath of Allegiance
After his speech, the Messenger of Allah asked every body to give the oath of allegiance to Imam `Ali (`a) and congratulate him. Among those who gave him the oath were H.Umar, H.Abu Bakr, and H.Uthman. It is narrated that H.Umar and H.Abu Bakr said: "Well done Ibn Abi Talib! Today you became the leader (Mawla) of all believing men and women."
Sunni references:
a.. Musnad Ahmad Ibn Hanbal, v4, p281
b.. Tafsir al-Kabir, by Fakhr al-Razi, v12, pp 49-50
c.. Mishkat al-Masabih, by al-Khatib al-Tabrizi, p557
d.. Habib al-Siyar, by Mir Khand, v1, part3, p144
e.. Kitabul Wilayah, by Ibn Jarir al-Tabari
f.. al-Musannaf, by Ibn Abi Shaybah
g.. al-Musnad, by Abu Ya'ala
h.. Hadith al-Wilayah, by Ahmad Ibn `Uqdah
i.. Tarikh, by Khatib al-Baghdadi, v8, pp 290,596 from Abu Hurayra... and more.