The clarification that the Qur’an was revealed in seven ahruf (modes of recitation), and clarifying its meaning Sahih Muslim 820 b
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، حَدَّثَنِي إِسْمَاعِيلُ بْنُ أَبِي، خَالِدٍ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ عِيسَى، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي لَيْلَى، أَخْبَرَنِي أُبَىُّ بْنُ كَعْبٍ، أَنَّهُ كَانَ جَالِسًا فِي الْمَسْجِدِ إِذْ دَخَلَ رَجُلٌ فَصَلَّى فَقَرَأَ قِرَاءَةً وَاقْتَصَّ الْحَدِيثَ بِمِثْلِ حَدِيثِ ابْنِ نُمَيْرٍ
Translation
Ubayy b. Ka'b reported that he was sitting in a mosque that a person entered it and he observed prayer, and made recitation, the rest of the hadith is the same.