Musannaf Ibn Abi Shayba 22:155

Abu Mu’awiyah narrated to us, from Hajjaj, from ‘Atiyyah, from Abu Sa’id, regarding the saying of the Exalted: "Say, 'In the bounty of Allah and in His mercy - in that let them rejoice.'" He said: "The bounty of Allah is the Qur’an, and His mercy is that He made you of its people."