(27) باب مَنْ لَمْ يَرَ بَأْسًا أَنْ يَقُولَ سُورَةُ الْبَقَرَةِ وَسُورَةُ كَذَا وَكَذَا
Narrated `Umar bin Khattab:
I heard Hisham bin Hakim bin Hizam reciting Surat-al-Furqan during the lifetime of Allah's Messenger (ﷺ), and I listened to his recitation and noticed that he recited it in several ways which Allah's Messenger (ﷺ) had not taught me. So I was on the point of attacking him in the prayer, but I waited till he finished his prayer, and then I seized him by the collar and said, "Who taught you this Surah which I have heard you reciting?" He replied, "Allah's Messenger (ﷺ) taught it to me." I said, "You are telling a lie; By Allah! Allah's Messenger (ﷺ) taught me (in a different way) this very Surah which I have heard you reciting." So I took him, leading him to Allah's Messenger (ﷺ) and said, "O Allah's Messenger (ﷺ)! I heard this person reciting Surat-al-Furqan in a way that you did not teach me, and you have taught me Surat-al-Furqan." The Prophet said, "O Hisham, recite!" So he recited in the same way as I heard him recite it before. On that Allah's Messenger (ﷺ) said, "It was revealed to be recited in this way." Then Allah's Messenger (ﷺ) said, "Recite, O `Umar!" So I recited it as he had taught me. Allah's Messenger (ﷺ) then said, "It was revealed to be recited in this way." Allah" Apostle added, "The Qur'an has been revealed to be recited in several different ways, so recite of it that which is easier for you."
Reference: Sahih al-Bukhari 5041
In-book reference: Book 66, Hadith 65
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 6, Book 61, Hadith 561