Musnad Abu Ya'la al-Mawsili 6:1

'Amr al-Naqid narrated to us, al-Walid narrated to us, Isma'il ibn Rafi' Abu Rafi' narrated to me, from Ibn Abi Mulaykah, from 'Abd al-Rahman ibn al-Sa'ib, who said: Sa'd ibn Malik came to us after he had lost his sight. I went to him to greet him, and I identified myself to him. He said: "Welcome, son of my brother. It has reached me that you have a beautiful voice with the Qur'an. I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: 'Indeed, this Qur'an was revealed with sadness (huzn), so when you recite it, weep. If you do not weep, then feign weeping, and beautify your voice with it (taghanna bihi). Whoever does not beautify his voice with it is not one of us.'"