Musnad Abu Ya'la al-Mawsili 1:61

Ishaq ibn Abi Isra'il narrated to us, Ibrahim ibn Sa'd narrated to us, Ibn Shihab narrated to us, from 'Ubayd ibn al-Sabbaq, from Zayd ibn Thabit, who said: Abu Bakr sent for me after the slaughter of the people of al-Yamamah. I came, and 'Umar was with him. He mentioned something similar to the hadith of al-'Umari, and added in it after Zayd ibn Thabit said: "So I attached it." Ibn Shihab said: They differed that day regarding the *tabut* (ark/coffin). Zayd said: *al-tabuh*, and the Qurayshi group said: *al-tabut*. They referred their disagreement to 'Uthman, and he said: "Write it as *al-tabut* in the tongue of Quraysh." Ibn Shihab said: Ibn Mas'ud had disliked that Zayd be entrusted with the copying of the codices (*masahif*). Ibn Shihab said: 'Ubayd Allah ibn 'Abd Allah narrated to me that 'Abd Allah [ibn Mas'ud] said: "O assembly of Muslims, am I to be removed from the Book of Allah and it be entrusted to a man? By Allah, I accepted Islam while he was still in the loins of a disbelieving man," meaning Zayd ibn Thabit. Ibn Shihab said: For that reason, 'Abd Allah said: "O people of Iraq, or O people of Kufa, conceal the codices that are with you and hide them, for Allah says: 'And whoever conceals [something], he will come with what he concealed on the Day of Resurrection' (Al 'Imran: 161)." Ibn Shihab said: It reached me that men who were among the most virtuous of the Companions of the Messenger of Allah (peace be upon him) disliked this statement of his.