Sahih Bukhari Volume 5, Book 58, Hadith Number 155.

Narated By Qatada : Anas said, “The Quran was collected in the lifetime of the Prophet by four (men), all of whom were from the Ansar: Ubai, Muadh bin Jabal, Abu Zaid and Zaid bin Thabit.” I asked Anas, “Who is Abu Zaid?” He said, “One of my uncles.”