Narrated Musa bin 'Uqba:
'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 Apostle saying, O Allah! Forgive the Ansar and the Ansar children. The subnarrator, Ibn Al-Fadl, is not sure whether the Prophet 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 Apostle ﷺ said, 'He is the one whose sound hearing Allah testified.'
Sahih al-Bukhari, Vol. 6, Book of Prophetic Commentary on the Qur'an, Hadith 429
Sahih al-Bukhari, Book of Prophetic Commentary on the Qur'an, Hadith 429