Sahih Bukhari
Merits of the Helpers in Madinah (Ansaar)
Volume: 005 / Book Number: 058 / Hadith Number: 155
Narrated 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."