Sahih Bukhari
Fighting for the Cause of Allah (Jihaad)
Volume: 004 / Book Number: 052 / Hadith Number: 62
Narrated Kharija bin Zaid:
Zaid bin Thabit said, "When the Quran was compiled from various written manuscripts, one of the Verses of Surat Al-Ahzab was missing which I used to hear Allah's Apostle reciting. I could not find it except with Khuzaima bin Thabjt Al-Ansari, whose witness Allah's Apostle regarded as equal to the witness of two men. And the Verse was:-- "Among the believers are men who have been true to what they covenanted with Allah." (33.23)