وَعَنِ ابْنِ مَسْعُودٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: سَمِعْتُ رَجُلًا قَرَأَ وَسَمِعْتُ
النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقْرَأُ خِلَافَهَا فَجِئْتُ بِهِ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَأَخْبَرْتُهُ فَعَرَفْتُ فِي وَجهه الْكَرَاهِيَة فَقَالَ: «كِلَاكُمَا مُحْسِنٌ فَلَا تَخْتَلِفُوا فَإِنَّ مَنْ كَانَ قبلكُمْ اخْتلفُوا فهلكوا»
I heard a man who recited, and as I had heard the Prophet (sallallahu alayhi wa sallam) reciting differently I took him to the Prophet (sallallahu alayhi wa sallam) and told him and noticed that he gave a disapproving look. He then said, “Both of you are doing it well, so do not disagree, for your predecessors disagreed and perished.” Bukhari transmitted it.
Mishkat al-Masabih 2116, Book 9, The Excellent Qualities of the Qur'an, Hadith 102. 1 min read