We think that the Verse: 'Among the Believers are men who have been true to their covenant with Allah.' was revealed in favor of Anas bin An-Nadir.
Sahih al-Bukhari Book 65, Hadith 305
← Previous Hadith We used not to call Zaid bin Haritha the freed slave of Allah's Messenger (ﷺ) except Zaid bin Muhammad till the Qu'anic Verse was revealed: "Call them (adopted sons) by (the names of) their fathers. That is more than just in the Sight of Allah." (33.5)

Sahih al-Bukhari Book 65, Hadith 304 Next Hadith → When we collected the fragramentary manuscripts of the Quran into copies, I missed one of the Verses of Surat al-Ahzab which I used to hear Allah's Messenger (ﷺ) reading. Finally I did not find it with anybody except Khuza`ima Al-Ansari, whose witness was considered by Allah's Messenger (ﷺ) equal to the witness of two men. (And that Verse was:) 'Among the believers are men who have been true to their covenant with Allah.'

Sahih al-Bukhari Book 65, Hadith 306