Mishkat al-Masabih 6:57

‘Uthmān b. ‘ Abdallāh b. Aus ath-Thaqafī, on his grandfather’s authority, reported God’s messenger as saying, “A man’s recitation of the Qur’ān without using a copy of it produces a thousand degrees of reward, but his recitation while using a copy is double that, reaching two thousand degrees.” Transmitted by Baihaqī in Shu'ab al-īmān .