Sahih Bukhari Volume 009, Book 091, Hadith Number 360.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 91. Accepting Information given by a Truthful Person
Narrated By Hudhaifa : The Prophet said to the people of Najran, "I will send to you an honest person who is really trustworthy." The Companion, of the Prophet each desired to be that person, but the Prophet sent Abu 'Ubaida.