Virtues of the Qur'an
حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُوسَى، عَنْ شَيْبَانَ، عَنْ يَحْيَى، عَنْ أَبِي سَلَمَةَ، قَالَ أَخْبَرَتْنِي عَائِشَةُ، وَابْنُ، عَبَّاسٍ رضى الله عنهم قَالاَ لَبِثَ النَّبِيُّ صلى الله عليه وسلم بِمَكَّةَ عَشْرَ سِنِينَ يُنْزَلُ عَلَيْهِ الْقُرْآنُ وَبِالْمَدِينَةِ عَشْرَ سِنِينَNarrated `Aisha and Ibn `Abbas:The Prophet (ﷺ) remained in Mecca for ten years, during which the Qur'an used to be revealed to him; and he stayed in Medina for ten years
From Sahih al-Bukhari, whose reports the scholars accept as authentic.