Sahih Bukhari
Good Manners and Form (Al-Adab)
Volume: 008 / Book Number: 073 / Hadith Number: 213
Narrated Said bin Al-Musaiyab:
That when his grandfather, Hazn visited the Prophet the Prophet said (to him), "What is your name?" He said, "My name is Hazn." The Prophet said, " But you are Sahl." He said, "I will not change my name with which my father named me." Ibn Al-Musaiyab added: So we have had roughness (in character) ever since.