Sahih al-Bukhari, Volume 4, Book 56, Hadith 737 (USC-MSA) ⓘ
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."
حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا شُعْبَةُ، عَنْ حُمَيْدٍ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلم فِي السُّوقِ فَقَالَ رَجُلٌ يَا أَبَا الْقَاسِمِ. فَالْتَفَتَ النَّبِيُّ صلى الله عليه وسلم فَقَالَ " سَمُّوا بِاسْمِي، وَلاَ تَكْتَنُوا بِكُنْيَتِي " .
also referenced under: Book 61, Hadith 46 (In-Book) & Hadith 3537 (DarusSalam)