Narrated `Aisha:The day of Bu'ath was a day (i.e. battle) which Allah caused to take place just before the mission of His Apostle so that when Allah's Messenger (ﷺ) came to Medina, they (the tribes) had divided (into hostile groups) and their nobles had been killed; and all that facilitated their conversion to Islam

English translation · Sahih al-Bukhari