Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))

Bukhari :: Book 6 :: Volume 60 :: Hadith 449

Narrated Ibn Abbas:

The Prophet used to move his tongue when the divine Inspiration was being revealed to him. (Sufyan, a subnarrator, demonstrated (how the Prophet used to move his lips) and added. "In order to memorize it." So Allah revealed: "Move not your tongue concerning (the Quran) to make haste therewith." (75.16)