The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fada'il Al-Sahabah)
Muslim :: Book 31 : Hadith 6108
Abu Usaid Ansar reported: I bear witness to the fact that Allah's Messenger (may peace be upon him) said: The best settlements of the Ansar are of those of Banu Najjar, then of Banu 'Abu al-Aslihal and then of Banu Harith b. Khazraj, then of Banu Sa'ida and there is in every settlement of the Ansar good. Abu Salama reported that Abu Usaid said: Can I tell a Iie about Allah's Messenger (may peace be upon him)? And if I were a liar, I would have started with my tribe Banu Sa'ida. This was conveyed to Sa'd b. 'Ubida and he found (rankling) in his mind and said: We have been left behind (in the sense) that we have been (mentioned) last of the four. He (Sa'd) sid: Saddle my pony so that I should go to Allah's Messenger (may peace be upon him). His nephew saw him and said: Are you going to contradict (the order of) precedence set by Allah's Messenger (may peace be upon him), whereas Allah's Messenger (may peace be upon him) has the best knowledge of it? Is it not sufficient for you that you are the fourth amongst the four (best tribes of the Ansar)? So he returned and said: Allah and His Messenger know best, and he commanded that his pony should be unsaddled.