Bukhari

Hadith Commentary:

Because the poor people remained, while the leaders and the wealthy had been killed. If all of them had been alive, perhaps due to arrogance they would not have become Muslims, and they would have prevented others from accepting Islam as well.

Bu'ath was the name of a place where this battle took place.

Hadith Commentary:
➊
The poor people remained in the blessed city of Madinah; the leaders and nobles had been killed.
If they had remained alive, perhaps due to their arrogance and pride, they would not have entered Islam.
If, at that time, there had not been discord among them, they would not have submitted to the Messenger of Allah (sallallahu alayhi wa sallam) in order to preserve their own rule.
➋
Only one leader, whose coronation was about to take place, caused great harm to Islam.
He did not let any opportunity pass by to defame the Muslims.
By this, we mean the chief of the hypocrites, Abdullah bin Ubayy.
In the end, he was humiliated at the hands of his own son.
Wallahu al-musta‘an (And Allah is the One whose help is sought).

Hadith Footnote:
Ba'ath or Bughath is a place located two miles from Madinah. There, a fierce battle took place between the two tribes of the Ansar, the Aws and the Khazraj. The chief of the Aws was Hudhayr, the father of Usayd, and the chief of the Khazraj was Amr ibn Nu'man al-Bayadi. Both of them were killed in this battle. Initially, the Khazraj were victorious, but then Hudhayr strengthened the Aws, resulting in the victory of the Aws. This incident occurred four or five years before the event of the Hijrah of the Prophet (sallallahu alayhi wa sallam). Upon the arrival of the Prophet (sallallahu alayhi wa sallam), these tribes embraced Islam and forgot all the events prior to Islamic brotherhood. The noble verse, ﴿فَأَصْبَحْتُمْ بِنِعْمَتِهِ إِخْوَانًا﴾ (Aal Imran: 103), alludes to this very matter.

Hadith Commentary:
Ba'ath:
It is a place located two miles from Madinah Tayyibah where a fierce battle took place between the Aws and Khazraj tribes. The chief of the Aws tribe was Hazrat Usayd’s (radi Allahu anhu) father, Khudayr, while the leader of the Khazraj was ‘Amr ibn Nu‘man Fayyad.
Both of them were killed in this battle.
At first, the Khazraj were victorious, then Khudayr strengthened the Aws tribe, so their side became dominant.
This battle took place five years before the migration (hijrah) of the Messenger of Allah (sallallahu alayhi wa sallam).
In it, many prominent leaders of both tribes were killed.
When Islam emerged, by the blessing of the arrival of the Messenger of Allah (sallallahu alayhi wa sallam), this conflict was ended forever, as if their being killed became a prelude to the spread of Islam.
If they had remained alive, their actions would have been strongly opposed to Islam.
Among these leaders was ‘Abdullah ibn Ubayy, who adopted the guise of hypocrisy.
The following noble verse alludes to this very reality:
“And remember Allah’s favor upon you when you were enemies, then He united your hearts, so by His grace you became brothers.” (Aal ‘Imran: 103/3)