Sahih al-Bukhari 4991
Sahih al-Bukhari · Book 66: Virtues of the Qur'an · The Qur'an was revealed to be recited in seven different ways
Narrated `Abdullah bin `Abbas:
حَدَّثَنَا سَعِيدُ بْنُ عُفَيْرٍ ، قَالَ حَدَّثَنِي اللَّيْثُ ، قَالَ حَدَّثَنِي عُقَيْلٌ ، عَنِ ابْنِ شِهَابٍ ، قَالَ حَدَّثَنِي عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ ، أَنَّ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ حَدَّثَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " أَقْرَأَنِي جِبْرِيلُ عَلَى حَرْفٍ فَرَاجَعْتُهُ، فَلَمْ أَزَلْ أَسْتَزِيدُهُ وَيَزِيدُنِي حَتَّى انْتَهَى إِلَى سَبْعَةِ أَحْرُفٍ " .
Allah's Messenger (ﷺ) said, "Gabriel recited the Qur'an to me in one way. Then I requested him (to read it in another way), and continued asking him to recite it in other ways, and he recited it in several ways till he ultimately recited it in seven different ways."