The clarification that the Qur’an was revealed in seven ahruf (modes of recitation), and clarifying its meaning Sahih Muslim 821 b
وَحَدَّثَنَاهُ عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا شُعْبَةُ، بِهَذَا الإِسْنَادِ مِثْلَهُ .
Translation
This hadith has been narrated by Shu'ba with the same chain of transmitters.