Sahih Muslim
The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fadail Al-Sahabah)
Book Number: 031 / Hadith Number: 6031
Anas b. Malik reported that Allah's Messenger (may peace be upon him) said to Ubayy: Verily Allah, the Exalted and Glorious, has commanded me to recite the Qur'an to you, whereupon he said: (Has) Allah mentioned my name to you? He said: Allah has mentioned your name to me. Thereupon he began to shed tears (of joy)