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."
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 237
Arabic reference: Book 65, Hadith 4713