It was narrated that Ubayy bin Ka'b said:

"The Messenger of Allah ﷺ taught me a surah, and when I was sitting in the masjid I heard a man reciting it in a way that was different from mine. I said to him: 'Who taught you this surah?' He said: 'The Messenger of Allah ﷺ.' I said: 'Stay with me until we go to the Messenger of Allah ﷺ.' So we came to him and I said: 'O Messenger of Allah, this man recites a surah that you taught me differently.' The Messenger of Allah ﷺ said: 'Recite, O Ubayy.' So I recited it, and the Messenger of Allah ﷺ said to me: 'You have done well.' Then he said to the man: 'Recite.' So he recited it and it was different to my recitation. The Messenger of Allah ﷺ said to him: 'You have done well.' Then the Messenger of Allah ﷺ said: 'O Ubayy, the Quran has been revealed with seven different modes of reciation, all of which are good and sound."

أَخْبَرَنِي عَمْرُو بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا أَبُو جَعْفَرِ بْنُ نُفَيْلٍ، قَالَ قَرَأْتُ عَلَى مَعْقِلِ بْنِ عُبَيْدِ اللَّهِ عَنْ عِكْرِمَةَ بْنِ خَالِدٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، عَنْ أُبَىِّ بْنِ كَعْبٍ، قَالَ أَقْرَأَنِي رَسُولُ اللَّهِ ﷺ سُورَةً فَبَيْنَا أَنَا فِي الْمَسْجِدِ جَالِسٌ إِذْ سَمِعْتُ رَجُلاً يَقْرَؤُهَا يُخَالِفُ قِرَاءَتِي فَقُلْتُ لَهُ مَنْ عَلَّمَكَ هَذِهِ السُّورَةَ فَقَالَ رَسُولُ اللَّهِ ﷺ . فَقُلْتُ لاَ تُفَارِقْنِي حَتَّى نَأْتِيَ رَسُولَ اللَّهِ ﷺ فَأَتَيْتُهُ فَقُلْتُ يَا رَسُولَ اللَّهِ إِنَّ هَذَا خَالَفَ قِرَاءَتِي فِي السُّورَةِ الَّتِي عَلَّمْتَنِي . فَقَالَ رَسُولُ اللَّهِ ﷺ " اقْرَأْ يَا أُبَىُّ " . فَقَرَأْتُهَا فَقَالَ لِي رَسُولُ اللَّهِ ﷺ " أَحْسَنْتَ " . ثُمَّ قَالَ لِلرَّجُلِ " اقْرَأْ " . فَقَرَأَ فَخَالَفَ قِرَاءَتِي فَقَالَ لَهُ رَسُولُ اللَّهِ ﷺ " أَحْسَنْتَ " . ثُمَّ قَالَ رَسُولُ اللَّهِ ﷺ " يَا أُبَىُّ إِنَّهُ أُنْزِلَ الْقُرْآنُ عَلَى سَبْعَةِ أَحْرُفٍ كُلُّهُنَّ شَافٍ كَافٍ " . قَالَ أَبُو عَبْدِ الرَّحْمَنِ مَعْقِلُ بْنُ عُبَيْدِ اللَّهِ لَيْسَ بِذَلِكَ الْقَوِيِّ .