Hadith 17:591
Ghundar narrated to us, from Shu'bah, from 'Ata' ibn Abi Maymunah, who said: I heard Abu Rafi' narrating from Abu Hurayrah that Zaynab's name was Barrah. It was said to her that she was purifying herself, so the Messenger of Allah, may Allah bless him and grant him peace, named her Zaynab.
حدثنا غندر عن شعبة عن عطاء بن أبي ميمونة قال سمعت أبا رافع يحدث عن أبي هريرة أن زينب كان اسمها برة فقيل لها تزكي نفسها فسماها رسول الله صلى الله عليه وسلم زينب