Narrated `Umar bin Al-Khattab:

I heard Hisham bin Hakim reciting Surat-al-Furqan during the lifetime of Allah's Messenger (ﷺ) , I listened to his recitation and noticed that he was reciting in a way that Allah's Messenger (ﷺ) had not taught me. I was about to jump over him while He was still in prayer, but I waited patiently and when he finished his prayer, I put my sheet round his neck (and pulled him) and said, "Who has taught you this Sura which I have heard you reciting?" Hisham said, "Allah's Messenger (ﷺ) taught it to me." I said, "You are telling a lie, for he taught it to me in a way different from the way you have recited it!" Then I started leading (dragged) him to Allah's Messenger (ﷺ) and said (to the Prophet), " I have heard this man reciting Surat-al- Furqan in a way that you have not taught me." The Prophet (ﷺ) said: "(O `Umar) release him! Recite, O Hisham." Hisham recited in the way I heard him reciting. Allah's Messenger (ﷺ) said, "It was revealed like this." Then Allah's Messenger (ﷺ) said, "Recite, O `Umar!" I recited in the way he had taught me, whereupon he said, "It was revealed like this," and added, "The Qur'an has been revealed to be recited in seven different ways, so recite of it whichever is easy for you ." (See Hadith No. 514, Vol. 6)

حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، حَدَّثَنِي عُرْوَةُ، أَنَّ الْمِسْوَرَ بْنَ مَخْرَمَةَ، وَعَبْدَ الرَّحْمَنِ بْنَ عَبْدٍ الْقَارِيَّ، حَدَّثَاهُ أَنَّهُمَا، سَمِعَا عُمَرَ بْنَ الْخَطَّابِ، يَقُولُ سَمِعْتُ هِشَامَ بْنَ حَكِيمٍ، يَقْرَأُ سُورَةَ الْفُرْقَانِ فِي حَيَاةِ رَسُولِ اللَّهِ صلى الله عليه وسلم فَاسْتَمَعْتُ لِقِرَاءَتِهِ، فَإِذَا هُوَ يَقْرَأُ عَلَى حُرُوفٍ كَثِيرَةٍ لَمْ يُقْرِئْنِيهَا رَسُولُ اللَّهِ صلى الله عليه وسلم، فَكِدْتُ أُسَاوِرُهُ فِي الصَّلاَةِ، فَتَصَبَّرْتُ حَتَّى سَلَّمَ، فَلَبَبْتُهُ بِرِدَائِهِ فَقُلْتُ مَنْ أَقْرَأَكَ هَذِهِ السُّورَةَ الَّتِي سَمِعْتُكَ تَقْرَأُ قَالَ أَقْرَأَنِيهَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَقُلْتُ كَذَبْتَ، أَقْرَأَنِيهَا عَلَى غَيْرِ مَا قَرَأْتَ‏.‏ فَانْطَلَقْتُ بِهِ أَقُودُهُ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَقُلْتُ إِنِّي سَمِعْتُ هَذَا يَقْرَأُ سُورَةَ الْفُرْقَانِ عَلَى حُرُوفٍ لَمْ تُقْرِئْنِيهَا‏.‏ فَقَالَ ‏"‏ أَرْسِلْهُ، اقْرَأْ يَا هِشَامُ ‏"‏‏.‏ فَقَرَأَ الْقِرَاءَةَ الَّتِي سَمِعْتُهُ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ كَذَلِكَ أُنْزِلَتْ ‏"‏‏.‏ ثُمَّ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ اقْرَأْ يَا عُمَرُ ‏"‏‏.‏ فَقَرَأْتُ الَّتِي أَقْرَأَنِي فَقَالَ ‏"‏ كَذَلِكَ أُنْزِلَتْ، إِنَّ هَذَا الْقُرْآنَ أُنْزِلَ عَلَى سَبْعَةِ أَحْرُفٍ فَاقْرَءُوا مَا تَيَسَّرَ مِنْهُ ‏"‏‏.‏