Sahih Bukhari Volume 6, Book 60, Hadith Number 307.

Narrated By Zaid bin Thabit : 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 Apostle reading. Finally I did not find it with anybody except Khuzaima Al-Ansari, whose witness was considered by Allah’s Apostle 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.’