Anas reported Allah's Messenger (ﷺ) as saying
For every Umma there is a man of trust and the man of trust of this Umma is Abu 'Ubaida b. Jarrah.
Anas reported that the people of Yemen came to Allah's Messenger (ﷺ) 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.
Hudhaifa reported that the people of Najran came to Allah's Messenger (ﷺ) and said
Allah's Messenger, send along with us a man of trust; whereupon he said: I would definitely send to you a man of trust, a man of trust in the true sense of the term. Thereupon his Companions looked up eagerly and he sent Abu Ubaida b. Jarrah.
This hadith has been reported on the authority of Abu Ishaq with the same chain of transmitters.