Is it for me to remain behind Allah's Messenger (ﷺ)? So he went forth and rejoined Allah's Apostle (ﷺ) and on the evening of that night (after which) next morning Allah granted victory. Allah's Messenger (ﷺ) said: I will certainly give this standard to a man whom Allah and His Messenger love. or he said: Who loves Allah or His Messenger and Allah will grant him victory through him, and, lo, we saw 'Ali whom we least expected (to be present on that occasion). They (the Companions) said: Here is 'Ali. Thereupon Allah's Messenger (may peace be upon hin) gave him the standard. Allah granted victory at his hand.
Sahih Muslim Book 44, Hadith 54
← Previous Hadith I would certainly give this standard to a person at whose hand Allah would grant victory and who loves Allah and His Messenger and Allah and His Messenger love him also. The people spent the night thinking as to whom it would be given. When it was morning the people hastened to Allah's Messenger (ﷺ) all of them hoping that that would be given to him. He (the Holy Prophet) said: Where is 'Ali b. Abu Talib? They said: Allah's Messenger, his eyes are sore. He then sent for him and he was brought and Allah's Messenger (ﷺ) applied saliva to his eyes and invoked blessings and he was all right, as if he had no ailment at all, and conferred upon him the standard. 'Ali said: Allah's Messenger, I will fight them until they are like us. Thereupon he (the Holy Prophet) said: Advance cautiously until you reach their open places, thereafter invite them to Islam and inform them what is obligatory for them from the rights of Allah, for, by Allah, if Allah guides aright even one person through you that is better for you than to possess the most valuable of the camels.

Sahih Muslim Book 44, Hadith 53 Next Hadith → Zaid. you have been able to acquire a great virtue that you saw Allah's Messenger (ﷺ) listened to his talk, fought by his side in (different) battles, offered prayer behind me. Zaid, you have in fact earned a great virtue. Zaid, narrate to us what you heard from Allah's Messenger (ﷺ). He said: I have grown old and have almost spent my age and I have forgotten some of the things which I remembered in connection with Allah's Messenger (ﷺ), so accept whatever I narrate to you, and which I do not narrate do not compel me to do that. He then said: One day Allah's Messenger (ﷺ) stood up to deliver sermon at a watering place known as Khumm situated between Mecca and Medina. He praised Allah, extolled Him and delivered the sermon and. exhorted (us) and said: Now to our purpose. O people, I am a human being. I am about to receive a messenger (the angel of death) from my Lord and I, in response to Allah's call, (would bid good-bye to you), but I am leaving among you two weighty things: the one being the Book of Allah in which there is right guidance and light, so hold fast to the Book of Allah and adhere to it. He exhorted (us) (to hold fast) to the Book of Allah and then said: The second are the members of my household I remind you (of your duties) to the members of my family. He (Husain) said to Zaid: Who are the members of his household? Aren't his wives the members of his family? Thereupon he said: His wives are the members of his family (but here) the members of his family are those for whom acceptance of Zakat is forbidden. And he said: Who are they? Thereupon he said: 'Ali and the offspring of 'Ali, 'Aqil and the offspring of 'Aqil and the offspring of Ja'far and the offspring of 'Abbas. Husain said: These are those for whom the acceptance of Zakat is forbidden. Zaid said: Yes.

Sahih Muslim Book 44, Hadith 55