In al-Masahif...

In al-Masahif, Ibn Abi Dawud reported on the authority of Abu Qullabah that he said: During his caliphate, Uthman gathered some individuals instructing that who had command over the Qur'an to teach others the correct way of reading it. Then there were meetings among the youths in which they differed in reciting the Qur'an, after which the teachers quarrelled over them accusing each other with kufr.

When Uthman become aware of this situation, he gathered the memorizers and qurra’, addressing them saying: I heard that you disagree and differ (regarding the reading of the Quran)... whoever is farther from me his…