Sahih Bukhari | Volume 8 | Hadith Number 211

Narrated by Sahl
When Al-Mundhir bin Abu Usaid was born, he was brought to the Prophet who placed him on his thigh. While Abu Usaid was sitting there, the Prophet was busy with something in his hands so Abu Usaid told someone to take his son from the thigh of the Prophet. When the Prophet finished his job (with which he was busy), he said, "Where is the boy?" Abu Usaid replied, "We have sent him home." The Prophet said, "What is his name?" Abu Usaid said, "(His name is) so-and-so. " The Prophet said, "No, his name is Al-Mundhir." So he called him Al-Mundhir from that day.