Sahih Bukhari Volume 3, Book 44, Hadith 2411

حَدَّثَنَا أَبُو الْوَلِيدِ، حَدَّثَنَا شُعْبَةُ، قَالَ عَبْدُ الْمَلِكِ بْنُ مَيْسَرَةَ أَخْبَرَنِي قَالَ سَمِعْتُ النَّزَّالَ، سَمِعْتُ عَبْدَ اللَّهِ، يَقُولُ سَمِعْتُ رَجُلاً، قَرَأَ آيَةً سَمِعْتُ مِنَ النَّبِيِّ، صلى الله عليه وسلم خِلاَفَهَا، فَأَخَذْتُ بِيَدِهِ، فَأَتَيْتُ بِهِ رَسُولَ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ كِلاَكُمَا مُحْسِنٌ ‏"‏‏.‏ قَالَ شُعْبَةُ أَظُنُّهُ قَالَ ‏"‏ لاَ تَخْتَلِفُوا فَإِنَّ مَنْ كَانَ قَبْلَكُمُ اخْتَلَفُوا فَهَلَكُوا ‏"‏‏.‏

Narrated By 'Abdullah : I heard a man reciting a verse (of the Holy Qur'an) but I had heard the Prophet reciting it differently. So, I caught hold of the man by the hand and took him to Allah's Apostle who said, "Both of you are right." Shu'ba, the sub-narrator said, "I think he said to them, "Don't differ, for the nations before you differed and perished (because of their differences)."