It is narrated from Sayyiduna Zayd bin Thabit (may Allah be pleased with him); he said: When the Prophet (peace and blessings be upon him) came to Madinah, Banu al-Najjar came to him (peace and blessings be upon him) and said: O Messenger of Allah, among us is a boy who has learned more than ten surahs of what has been revealed to you. So the Messenger of Allah (peace and blessings be upon him) called me, and I recited before him (peace and blessings be upon him).
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 4844