Musannaf Ibn Abi Shayba 22:125

Waki’ narrated to us, from Hisham al-Dastawa’i, from Qatadah, from Zurarah ibn Awfa, from Sa’d ibn Hisham, from ‘Aishah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The one who recites the Qur’an while he is proficient in it is with the noble, righteous scribes. And the one who recites it while it is difficult for him has two rewards."