Sahih Muslim
The Book on General Behaviour (Kitab Al-Adab)
Book Number: 025 / Hadith Number: 5337
Muhammad b. 'Amr b. 'Ata' reported: I had given the name Barra to my daughter. Zainab, daughter of Abu Salama, told me that Allah's' Messenger (may peace be upon him) had forbidden me to give this name. (She said): I was also called Barra, but Allah's Messenger (may peace be upon him) said: Don't hold yourself to be pious. It is God alone who knows the people of piety among you. They (the Companions) said: Then, what name should we give to her? He said: Name her as Zainab.