Da'wat Dhul Ashira: Summoning the Family, the First Open Call to Islam
Tarikh al-Tabari, Vol. 6, Page 91
Narrated Rabi'ah b. Najid:

A man said to 'Ali, "Commander of the Faithful, how did you become the heir of your cousin to the exclusion of your paternal uncle?"

 

'Ali said, "Ahem" three times until everybody craned their necks and pricked up their ears, and then said, "The Messenger of God assembled (or: invited) the whole of the Banu 'Abd al-Muttalib, including his own closest relatives, to eat a year-old lamb and to drink some milk. He also prepared a quantity of wheat for them, and they ate until they were full, while the food remained as it was, as though it had not been touched. the he called for a drinking cup and they drank until they could drink no more, while the drink remained as though it had not been touched and they had not drunk.

 

"Then he said, Banu 'Abd al-Muttalib, I have been sent to all men in general and to you in particular. Now that you have seen what you have seen, which of you will swear an oath of allegiance to me to become my brother, my companion and my inheritor?' None of them rose up, so I stood before him, although I was the youngest there. He said 'Sit down.' He repeated the words he had spoken three times, while I would rise up and would say to me, 'Sit down.' On the third occasion, he stuck his hand on mine. In this way I became the heir of my cousin to the exlusion of my uncle."

Book  : Tarikh at-Tabari
Author  : Muhammad ibn Jarir al-Tabari (224 AH - 310 AH)
English reference  : Vol. 6, Page 89
Arabic reference  : 
Narrated by: Zakariyya' b. Yahya al-Darir, from 'Affan b. Muslim, from Abu 'Awanah, from 'Uthman b. al-Mughirah, from Abu Sadiq, from Rabi'ah b. Najid.