These two are related to conflicts in the recitation of the Quran.
Mr Violence classic.
Sahi Bukhari 3.601:
Narrated `Umar bin Al−Khattab: I heard Hisham bin Hakim bin Hizam reciting Surat−al−Furqan in a way different to that of mine. Allah's Apostle had taught it to me (in a different way). So, I was about to quarrel with him (during the prayer) but I waited till he finished, then I tied his garment round his neck and seized him by it and brought him to Allah's Apostle and said, "I have heard him reciting Surat−al−Furqan in a way different to the way you taught it to me." The Prophet ordered me to release him and asked Hisham to recite it. When he recited it, Allah s Apostle said, "It was revealed in this way." He then asked me to recite it. When I recited it, he said, "It was revealed in this way. The Qur'an has been revealed in seven different ways, so recite it in the way that is easier for you."
Umar bin Al-Khattab and Hisham bin Hakim were from the same tribe, therefore, this difference was not a matter of dialect.
Uthman confirms Quran revealed in dialect of Quraish
Chest thump classic.
Sahi Muslim Bk 4, Number 1787:
Ubayy b. Ka'b reported: I was in the mosque when a man entered and prayed and recited (the Qur'in) in a style to which I objected. Then another man entered (the mosque) and recited in a style different from that of his companion. When we had finished the prayer, we all went to Allah's Messenger (may peace be upon him) and said to him: This man recited in a style to which I objected, and the other entered and recited in a style different from that of his companion. The Messenger of Allah (may peace be upon him) asked them to recite and so they recited, and the Apostle of Allah (may peace be upon him) expressed approval of their affairs (their modes of recitation). and there occurred In my mind a sort of denial which did not occur even during the Days of Ignorance. When the Messenger of Allah (may peace be upon him) saw how I was affected (by a wrong idea), he struck my chest, whereupon I broke into sweating and felt as though I were looking at Allah with fear. He (the Holy Prophet) said to me: Ubayy. a message was sent to me to recite the Qur'an in one dialect, and I replied: Make (things) easy for my people. It was conveyed to me for the second time that it should be recited in two dialects. I again replied to him: Make affairs easy for my people. It was again conveyed to me for the third time to recite in seven dialects And (I was further told): You have got a seeking for every reply that I sent you, which you should seek from Me. I said: O Allah! forgive my people, forgive my people, and I have deferred the third one for the day on which the entire creation will turn to me, including even Ibrahim (peace be upon him) (for intercession).