سنن النسائي

It was narrated from Ibn Makhramah that: Umar bin Al-Khattab, may Allah be pleased with him, said: "I heard Hisham bin Hakim bin Hizam reciting: Surat Al-Furqan, in a way that the Prophet (ﷺ) of Allah (ﷺ) had not taught me. I said: 'Who taught you this Surah?' He said: 'The Messenger of Allah (ﷺ).' I said: 'You are lying; the Messenger of Allah (ﷺ) did not teach you like that. 'I took him by the hand and brought him to the Messenger of Allah (ﷺ) and said: 'O Messenger of Allah, you taught me Surat Al-Furqan, but I heard this man reciting it in a way that you did not teach me.' The Messenger of Allah (ﷺ) said: 'Recite, O Hisham.' So he recited it as he had recited it (before). The Messenger of Allah (ﷺ) said: 'It was revealed like this.' Then he said: 'Recite, O Umar.' So I recited it, and he said: 'It was revealed like this.' Then the Messenger of Allah (ﷺ) said: 'The Quran was revealed to be recited in seven different modes.'"