Sahih Muslim Book 4, Hadith Number 1783.

Chapter : Excellence of one who acts upon (the teachings of the) Qur’an and one who teaches it.

This Hadith has been transmitted thus by ‘Umar b. Khattab (with a slight change of words): “I heard Hisham b. Hakim reciting Surah al-Furqan during the lifetime of Allah’s Messenger (may peace be upon him).” The rest is the same but with this addition: “I was about to catch hold of him in prayer, but I exercised patience till he pronounced salutation.