Sahih Bukhari
Virtues and Merits of the Prophet (pbuh) and his Companions
Volume: 004 / Book Number: 056 / Hadith Number: 737
Narrated Anas:
While the Prophet was in the market, a man called (somebody), "O Abu-l-Qasim!' The Prophet turned to him and said "Name yourselves after me but do not call yourselves by my Kuniya."