Event of Gadheer
"For whoever I am his Leader (Mawla), 'Ali is his Leader (Mawla)." -Holy Prophet (Sawa)in his sermon after Last Hajj
18th Zilhajj

On 18th of Dhul-hijjah in 10 A.H. (10 March 632 CE), after completing the last pilgrimage, the Holy Prophet (sawa) along with around 100,000 Muslims reached a place called 'Ghadir-e-Khumm' near Mecca. The following verse was revealed :
O Messenger! Deliver what bas been revealed to you from your Lord; and if you do it not, then you have not delivered His message, and Allah will protect you from the people; surely Allah will not guide the unbelieving people. [Quran 5:67]
On receiving the above verse, the Holy Prophet (peace and blessings be upon him and his family) stopped at that very place and delivered a sermon (Complete sermon click here) an extract of which is as follows:
"..It seems the time has approached when I shall be called away by Allah.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 Paradise)."
Then the Holy Prophet (peace and blessings be upon him and his family) in an attempt to remind Muslims of his own authority over them said:
"Do I not have more right over the believers than what they have over themselves? "
Muslims answered unanimously "Yes, O' Messenger of God"
This served as a stepping stone for the announcement of his heir and vicegerent.
The Holy Prophet (sawa) held out the hand of Ali (as) and said:
"For whoever I am his Leader (Mawla), 'Ali is his Leader (Mawla)."
The Holy Prophet (sawa) then continued to say:
" O' God, love those who love him, and be hostile to those who are hostile to him."
It was subsequent to the announcement that the following verse was revealed.
“This day have I perfected for you your religion and completed My favor on you and chosen for you Islam as a religion.” .[Surah al-Ma`idah 5:3]
Isn’t it astounding that the most narrated incident of the Prophet’s life, mentioned by 110 companions and over 300 Tabieen, is one that most Muslims don’t even know about?
To say the Prophet died without appointing a successor is accusing the Prophet of risking his life long message which he struggled so much for. Why would the divinely guided Prophet do such a thing?!

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Ahlulbayt(as) in the Quran
1."Verily,Allah has decreed to purify you, O ' Ahlul Bayt, and sanctify you in a perfect way” Sura Ahzab no.33:33 Sunni ref
إنَّمَا يُرِيدُ اللَّهُ لِيُذْهِبَ عَنكُمُ الرِّجْسَ أَهْلَ الْبَيْتِ وَيُطَهِّرَكُمْ تَطْهِيرًا

2.Love (Mawaddat) of the Prophets Family ( Qurba) is the mandatory recompense for his services benefitting ourselves Quran 42:23 ;Declare [O' Muhammad]: “I ask you of no recompense for my toil except the love for my kin (family).”
قُل لا أَسْأَلُكُمْ عَلَيْهِ أَجْرًا إِلا الْمَوَدَّةَ فِي الْقُرْبَى وَمَن يَقْتَرِفْ حَسَنَةً نَّزِدْ لَهُ فِيهَا حُسْنًا إِنَّ اللَّهَ غَفُورٌ شَكُورٌ

More references of Ahlulbayt (as) in Quran | )PDF'
3) "Wali" (overlord ) along with Allah (swt) and the Prophet(saw),who gives zakat whilst bowing in Rukoo.- Q 5:55
4) 'Ul ul-'amr " (those vested with Authority) whose obedience along with Allah (swt) and HIS Prophet(saws) is compulsory- Q 4:59
5) "Abna, Nisa and Anfos" (sons, women, self) who accompanied Prophet(saw) in the Mubahila victory.- Q 3:61
6) "Ahlul Dhikr" (Folks of the Quran)- to whom we are commanded to ask what we do not know. -Q 16:43.
7) "Rasikhoon fil I'lm" (erudite in knowledge of the Divine) who know the inner meaning of Quran-Q 3: 7.
8) "Aal" (Family) who must be compulsorily saluted in tashahud for the obligatory prayer to be valid.-Q 33:56

Additonal sources of Ahlulbayt (as) in' Quran

The infalliables through the Quran