Umar bin Khattab reported,

Umar said, "I heard Hisham bin Hakeem bin Hizam reciting Surah al-Furqan during the lifetime of the Messenger of Allah ﷺ. I listened carefully to his recitation, and found that he was reciting it in many ways that the Messenger of Allah ﷺ had not taught me. I nearly leapt at him while he was still in prayer, but I restrained myself until he had given the closing salam. Then I seized him by his cloak and asked, 'Who taught you to recite this surah the way I just heard you recite it?'He replied, 'The Messenger of Allah ﷺ taught me.'I said, 'You are lying. The Messenger of Allah ﷺ taught me to recite it differently from the way you have recited it.'So I took him by the hand and led him to the Messenger of Allah ﷺ and said, 'I heard this man reciting Surah al-Furqan in ways you did not teach me.'The Messenger of Allah ﷺ said, 'Let him go. Recite, Hisham.'So Hisham recited it for him in the manner I had heard.The Messenger of Allah ﷺ said, 'Thus it was revealed.'Then he said, 'Recite, Umar.'So I recited it as he had taught me.The Messenger of Allah ﷺ said, 'Thus it was revealed. This Quran was revealed in seven modes, so recite from it whatever is easy for you.'"

عمر بن الخطاب يقول

سمعت هشام بن حكيم بن حزام يقرأ سورة الفرقان في حياة رسول الله ﷺ، فاستمعت لقراءته، فإذا هو يقرأ على حروف كثيرة لم يقرنيها رسول الله ﷺ، فكدت أساوره في الصلاة، فتصبرت حتى سلم، فلببته بردائه، فقلت: من أقرأك هذه السورة التي سمعتك تقرأ؟ قال: أقرأنيها رسول الله ﷺ، فقلت: كذبت، فإن رسول الله ﷺ أقرأنيها على غير ما قرأت، فانطلقت به أقوده إلى رسول الله ﷺ، فقلت: إني سمعت هذا يقرأ بسورة الفرقان على حروف لم تقرئنيها! فقال رسول الله ﷺ: أرسله، اقرأ يا هشام. فقرأ عليه القراءة التي سمعته يقرأ. فقال رسول الله ﷺ: كذلك أنزلت. ثم قال: اقرأ يا عمر. فقرأت القراءة التي أقرأني. فقال رسول الله ﷺ: كذلك أنزلت إن هذا القرآن أنزل على سبعة أحرف، فاقرأوا ما تيسر منه.