Narrated 'Aisha: Allah caused the day of Buath to take place before Allah's Apostle was sent (as an Apostle) so that when Allah's Apostle reached Medina, those people had already divided (in different groups) and their chiefs had been killed or wounded. So Allah made that day precede Allah's Apostle so that they (i.e. the Ansar) might embrace Islam.

Narrated `Aisha: The day of Bu'ath (i.e. Day of fighting between the two tribes of the Ansar, the Aus and Khazraj) was brought about by Allah for the good of His Apostle so that when Allah's Apostle reached (Medina), the tribes of Medina had already divided and their chiefs had been killed and wounded. So Allah had brought about the battle for the good of H is Apostle in order that they (i.e. the Ansar) might embrace Islam.