Musannaf Ibn Abi Shayba 22:90

Isma'il ibn 'Ulayyah narrated to us, from al-Jurayri, from Abu Nadrah, from Abu Firas, who said: 'Umar said: "A time has come upon me when I used to think that whoever read the Qur'an, he intended by it the Face of Allah. Now, lately, it has been imagined to me that I see people who have read it intending by it the people. So, intend Allah with your recitation, and intend Allah with your deeds."