مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3882
Musnad of Abdullah bin Mas'ood
An-Nazzal bin Sabrah said: I heard a man reciting a verse differently than the way the Messenger of Allah (ﷺ) taught it to me, so I took him by the hand and brought him to the Messenger of Allah (ﷺ), who said: “Both of you are good; do not differ." To the best of my knowledge, or as Mis'ar narrated it to me, “For those who came before you differed concerning it, then they were doomed."
Musnad Ahmad 3907Its isnad is saheeh, al-Bukhari (2410) it is a repeat of (37