Musnad Ahmad

Sayyiduna Ali (may Allah be pleased with him) narrates that once the Prophet (peace and blessings be upon him) gathered the Banu Abdul Muttalib for a meal. Among them were some people who could eat an entire kid goat and drink sixteen ratl of water. The Prophet (peace and blessings be upon him) had only one mudd (for ease, assume one kilogram) of food prepared for all of them. When they began to eat, all of them became full from that small amount of food, and the food remained as it was, as if no one had touched it. Then the Prophet (peace and blessings be upon him) asked for a little water, and all of them drank to their fill, but the water remained as it was, as if no one had touched it. After completing all these stages, the Prophet (peace and blessings be upon him) addressed them and said: "O Banu Abdul Muttalib! I have been sent specifically to you and generally to all of humanity, and you have just witnessed this miracle of food. Now, who among you will pledge allegiance to me on the condition that he will be my brother and my companion?" No one stood up at this. Seeing this—and although I was the youngest—I stood up. The Prophet (peace and blessings be upon him) ordered me to sit down and repeated his statement three times, and each time the same happened: I would stand up and the Prophet (peace and blessings be upon him) would order me to sit down, until the third time the Prophet (peace and blessings be upon him) placed his hand on my hand (and accepted my pledge of allegiance).