Chapter 39: The Book of Manners and Etiquette
Sahl b. Sa' d reported that Mundhir b. Aba Usaid was brought to Allah' s Messenger (ﷺ) at the time of his birth Allah' s. Apostle (ﷺ) placed him on his thigh and Abfi Usaid kept sitting there. Allah' s Apostle (ﷺ) had been occupied with something else before him. Abu Usaid commanded his child to be lifted from the lap of Allah' s Messenger (ﷺ) and so he was lifted. When Allah' s Messenger (ﷺ) had finished the work he said: Where is the child? Abd Usaid said: Allah' s Messenger, we took him away. He said: What is his name? He said; Allah' s Messenger, it is so and so, whereupon he (the Holy Prophet) said: Nay, his name is Mundhir, and named him Mundhir on that day.
Sahih Muslim 2149