Sunan an-Nasa'i, Book 11, Hadith 66 (In-Book) ⓘ

It was narrated that Ubayy said: "I had no confusion in my mind from that time I embraced Islam, except when I recited a verse and another man recited it differently. I said: 'The Messenger of Allah taught me this.' And the other man said: 'The Messenger of Allah taught me too.' So I went to the Prophet and said: 'O Prophet of Allah, did you not teach me such and such a verse?' He said: 'Yes.' The other man said: 'Did you not teach me such and such a verse?' He said: 'Yes. Jibril and Mika'il, peace be upon them, came to me, and Jibril sat on my right and Mika'il on my left. Jibril, peace be upon him, said: "Recite the Quran with one way of recitation.' Mika'il said: 'Teach him more, teach him more- until there were seven modes of recitation, each of which is good and sound.'"

أَخْبَرَنِي يَعْقُوبُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ حُمَيْدٍ، عَنْ أَنَسٍ، عَنْ أُبَىٍّ، قَالَ مَا حَاكَ فِي صَدْرِي مُنْذُ أَسْلَمْتُ إِلاَّ أَنِّي قَرَأْتُ آيَةً وَقَرَأَهَا آخَرُ غَيْرَ قِرَاءَتِي فَقُلْتُ أَقْرَأَنِيهَا رَسُولُ اللَّهِ صلى الله عليه وسلم ‏.‏ وَقَالَ الآخَرُ أَقْرَأَنِيهَا رَسُولُ اللَّهِ صلى الله عليه وسلم ‏.‏ فَأَتَيْتُ النَّبِيَّ صلى الله عليه وسلم فَقُلْتُ يَا نَبِيَّ اللَّهِ أَقْرَأْتَنِي آيَةَ كَذَا وَكَذَا قَالَ ‏"‏ نَعَمْ ‏"‏ ‏.‏ وَقَالَ الآخَرُ أَلَمْ تُقْرِئْنِي آيَةَ كَذَا وَكَذَا قَالَ ‏"‏ نَعَمْ إِنَّ جِبْرِيلَ وَمِيكَائِيلَ عَلَيْهِمَا السَّلاَمُ أَتَيَانِي فَقَعَدَ جِبْرِيلُ عَنْ يَمِينِي وَمِيكَائِيلُ عَنْ يَسَارِي فَقَالَ جِبْرِيلُ عَلَيْهِ السَّلاَمُ اقْرَإِ الْقُرْآنَ عَلَى حَرْفٍ ‏.‏ قَالَ مِيكَائِيلُ اسْتَزِدْهُ اسْتَزِدْهُ حَتَّى بَلَغَ سَبْعَةَ أَحْرُفٍ فَكُلُّ حَرْفٍ شَافٍ كَافٍ ‏"‏ ‏.‏