Musnad Ahmad 938:77

'Abd al-Razzaq narrated to us, Ma'mar informed us, from al-Zuhri, from Kharijah ibn Zayd, or someone else, that Zayd ibn Thabit said: "When the copies of the Qur'an were written, I missed an ayah that I used to hear from the Messenger of Allah, may Allah bless him and grant him peace. I found it with Khuzaymah al-Ansari: 'Among the believers are men true to what they covenanted Allah for' [al-Ahzab: 23], up to '...any change' [al-Ahzab: 23]." He said: "Khuzaymah used to be called 'Dhu al-Shahadatayn' (the possessor of two testimonies), for the Messenger of Allah, may Allah bless him and grant him peace, permitted his testimony as the testimony of two men." Al-Zuhri said: "And he was killed on the day of Siffin with Ali, may Allah be pleased with them both."