Sahih Bukhari | Volume 4 | Hadith Number 697
Narrated by Kulaib bin Wail
I asked Zainab bint Abi Salama (i.e. daughter of the wife of the Prophet, "Tell me about the Prophet. Did he belong to the tribe of Mudar?" She replied, "Yes, he belonged to the tribe of Mudar and was from the offspring of An-Nadr bin Kinana."