Sahih al-Bukhari Book 65, Hadith 305
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.
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)
When we collected the fragramentary manuscripts of the Qur'an 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.'