Virtues and Merits of the Prophet (pbuh) and his Companions

Bukhari :: Book 4 :: Volume 56 :: Hadith 709

Narrated Anas:

Uthman called Zaid bin Thabit, Abdullah bin Az-Zubair, Said bin Al-'As and 'AbdurRahman bin Al-Harith bin Hisham, and then they wrote the manuscripts of the Holy Qur'an in the form of book in several copies. 'Uthman said to the three Quraishi persons. " If you differ with Zaid bin Thabit on any point of the Quran, then write it in the language of Quraish, as the Quran was revealed in their language." So they acted accordingly. (Said bin Thabit was an Ansari and not from Quraish ).