(49) باب مَا ذُكِرَ فِي الأَسْوَاقِ
Narrated Anas bin Malik:
While the Prophet (ﷺ) was in the market, somebody, called, "O Abul-Qasim." The Prophet (ﷺ) turned to him. The man said, "I have called to this (i.e. another man)." The Prophet (ﷺ) said, "Name yourselves by my name but not by my Kunya (name)." (In Arabic world it is the custom to call the man as the father of his eldest son, e.g. Abul-Qasim.) (See Hadith No. 737, Vol. 4)
Reference: Sahih al-Bukhari 2120
In-book reference: Book 34, Hadith 73
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 34, Hadith 331