Sahih al-Bukhari 2419
Narrated `Umar bin Al-Khattab:
I heard Hisham bin Hakim bin Hizam reciting Surat-al-Furqan in a way different to that of mine. 
Allah's Messenger (ﷺ) had taught it to me (in a different way). So, I was about to quarrel with him (during 
the prayer) but I waited till he finished, then I tied his garment round his neck and seized him by it and 
brought him to Allah's Messenger (ﷺ) and said, "I have heard him reciting Surat-al-Furqan in a way different 
to the way you taught it to me." The Prophet (ﷺ) ordered me to release him and asked Hisham to recite it. 
When he recited it, Allah s Apostle said, "It was revealed in this way." He then asked me to recite it. 
When I recited it, he said, "It was revealed in this way. The Qur'an has been revealed in seven 
different ways, so recite it in the way that is easier for you."
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَبْدٍ الْقَارِيِّ، أَنَّهُ قَالَ سَمِعْتُ عُمَرَ بْنَ الْخَطَّابِ ـ رضى الله عنه ـ يَقُولُ سَمِعْتُ هِشَامَ بْنَ حَكِيمِ بْنِ حِزَامٍ، يَقْرَأُ سُورَةَ الْفُرْقَانِ عَلَى غَيْرِ مَا أَقْرَؤُهَا، وَكَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم أَقْرَأَنِيهَا، وَكِدْتُ أَنْ أَعْجَلَ عَلَيْهِ، ثُمَّ أَمْهَلْتُهُ حَتَّى انْصَرَفَ، ثُمَّ لَبَّبْتُهُ بِرِدَائِهِ فَجِئْتُ بِهِ رَسُولَ اللَّهِ صلى الله عليه وسلم فَقُلْتُ إِنِّي سَمِعْتُ هَذَا يَقْرَأُ عَلَى غَيْرِ مَا أَقْرَأْتَنِيهَا، فَقَالَ لِي ‏"‏ أَرْسِلْهُ ‏"‏‏.‏ ثُمَّ قَالَ لَهُ ‏"‏ اقْرَأْ ‏"‏‏.‏ فَقَرَأَ‏.‏ قَالَ ‏"‏ هَكَذَا أُنْزِلَتْ ‏"‏‏.‏ ثُمَّ قَالَ لِي ‏"‏ اقْرَأْ ‏"‏‏.‏ فَقَرَأْتُ فَقَالَ ‏"‏ هَكَذَا أُنْزِلَتْ‏.‏ إِنَّ الْقُرْآنَ أُنْزِلَ عَلَى سَبْعَةِ أَحْرُفٍ فَاقْرَءُوا مِنْهُ مَا تَيَسَّرَ ‏"‏‏.‏