Sayyiduna Zayd bin Thabit (may Allah be pleased with him) said: When we wrote the copies of the Qur'an (masahif), I could not find a verse that I used to hear from the Messenger of Allah (peace and blessings be upon him); then I found that verse with Sayyiduna Khuzaymah bin Thabit al-Ansari (may Allah be pleased with him): "Among the believers are men who have been true to the covenant they made with Allah. Among them is he who has fulfilled his vow, and among them is he who is waiting, and they have not altered (it) in the least" [Surah al-Ahzab: 23]. The narrator said: "And Khuzaymah (may Allah be pleased with him) used to be called Dhu al-Shahadatayn (the one whose testimony counted as two)."
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3697