Sahih al-Bukhari 4713
Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · Narrated by Abu Huraira
Arabic
حَدَّثَنِي إِسْحَاقُ بْنُ نَصْرٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، عَنْ مَعْمَرٍ، عَنْ هَمَّامٍ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " خُفِّفَ عَلَى دَاوُدَ الْقِرَاءَةُ، فَكَانَ يَأْمُرُ بِدَابَّتِهِ لِتُسْرَجَ، فَكَانَ يَقْرَأُ قَبْلَ أَنْ يَفْرُغَ ". يَعْنِي الْقُرْآنَ.
English translation
Narrated Abu Huraira:The Prophet (ﷺ) said, "The recitation of Psalms (David's Qur'an) was made light and easy for David that he used to have his ridding animal be saddled while he would finish the recitation before the servant had saddled it
Reference: Sahih al-Bukhari 4713, Book of Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)). English translation by Dr. Muhammad Muhsin Khan.