Sahih Muslim Book 31, Hadith Number 5948.
Chapter : The merits of Abu Ubaida b. Jarrah (Allah be pleased with him).
Anas reported that the people of Yemen came to Allah’s Messenger (may peace be upon him) and said: Send with us a person who should teach us Sunnah and al-Islam, whereupon he (the Holy Prophet) caught hold of the hand of Ubaida and said: He is a man of trust of this Umma.