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Narrated Anas bin Malik:(The Caliph `Uthman ordered Zaid bin Thabit, Sa`id bin Al-As, `Abdullah bin Az-Zubair and `Abdur-Rahman bin Al-Harith bin Hisham to write the Qur'an in the form of a book (Mushafs) and said to them. "In case you disagree with Zaid bin Thabit (Al-Ansari) regarding any dialectic Arabic utterance of the Qur'an, then write it in the dialect of Quraish, for the Qur'an was revealed in this dialect." So they did it.