The Messenger of Allah said to the people of Najran: "I will send you a trustworthy man with you, who is indeed trustworthy." The people craned their necks to see, and he sent Abu 'Ubaidah bin Jarrah. (Using translation from Ibn Mājah 135)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ لِأَهْلِ نَجْرَانَ لَأَبْعَثَنَّ إِلَيْكُمْ رَجُلًا أَمِينًا حَقَّ أَمِينٍ قَالَهَا أَكْثَرَ مِنْ مَرَّتَيْنِ فَاسْتَشْرَفَ لَهَا النَّاسُ فَبَعَثَ أَبَا عُبَيْدَةَ