`Abdullah bin Al-Fadl told me that Anas bin Malik said, "I was much grieve over those who had been killed in the Battle of Al-Harra. When Zaid bin Arqarr heard of my intense grief (over the killed Ansar), he wrote a letter to me saying that he heard Allah's Messenger (ﷺ) saying, O Allah! Forgive the Ansar and the Ansar children. The subnarrator, Ibn Al-Fadl, is not sure whether the Prophet (ﷺ) also said, And their grand-children." Some of those who were present, asked Anas (about Zaid). He said, "He (Zaid) is the one about whom Allah's Messenger (ﷺ) said, 'He is the one whose sound hearing Allah testified.'
Sahih al-Bukhari Book 65, Hadith 426
← Previous Hadith We were in a Ghazwa (Sufyan once said, in an army) and a man from the emigrants kicked an Ansari man (on the buttocks with his foot). The Ansari man said, "O the Ansar! (Help!)" and the emigrant said. "O the emigrants! (Help!) Allah's Messenger (ﷺ) heard that and said, "What is this call for, which is characteristic of the period of ignorance?" They said, "O Allah's Messenger (ﷺ)! A man from the emigrants kicked one of the Ansar (on the buttocks with his foot)." Allah's Messenger (ﷺ) said, "Leave it (that call) as is a detestable thing." `Abdullah bin Ubai heard that and said, 'Have the (the emigrants) done so? By Allah, if we return Medina, surely, the more honorable will expel therefrom the meaner." When this statement reached the Prophet. `Umar got up an, said, "O Allah's Messenger (ﷺ)! Let me chop off the head of this hypocrite (`Abdullah bin Ubai)!" The Prophet (ﷺ) said "Leave him, lest the people say that Muhammad kills his companions." The Ansar were then more in number than the emigrants when the latter came to Medina, but later on the emigrant increased.

Sahih al-Bukhari Book 65, Hadith 425 Next Hadith → We were in a Ghazwa and a man from the emigrants kicked an Ansari (on the buttocks with his foot). The Ansari man said, "O the Ansari! (Help!)" The emigrant said, "O the emigrants! (Help)." When Allah's Messenger (ﷺ) heard that, he said, "What is that?" They said, "A man from the emigrants kicked a man from the Ansar (on the buttocks his foot). On that the Ansar said, 'O the Ansar!' and the emigrant said, 'O the emigrants!" The Prophet (ﷺ) said' "Leave it (that call) for it Is a detestable thing." The number of Ansar was larger (than that of the emigrants) at the time when the Prophet (ﷺ) came to Medina, but later the number of emigrants increased. `Abdullah bin Ubai said, "Have they, (the emigrants) done so? By Allah, if we return to Medina, surely, the more honorable will expel therefrom the meaner," `Umar bin Al-Khattab said, "O Allah's Messenger (ﷺ)! Let me chop off the head of this hypocrite!" The Prophet said, "Leave him, lest the people say Muhammad kills his companions:"

Sahih al-Bukhari Book 65, Hadith 427