Sahih Bukhari
Sahih Bukhari Volume 009, Book 091, Hadith Number 361.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 91. Accepting Information given by a Truthful Person
Narrated By Anas : The Prophet said, "For every nation there is an Amin (honest, trustworthy person) and the Amin of this nation is Abu 'Ubaida."