A delegation from Yemen came to the Messenger of Allah ﷺ and said, "Send with us a man who can teach us the Sunnah and Islam."He took Abu Ubayda by the hand and said, "This is the trustworthy one of this nation."
حدثني عمرو الناقد حدثنا عفان حدثنا حماد وهو ابن سلمة عن ثابت
أن أهل اليمن قدموا على رسول الله ﷺ فقالوا ابعث معنا رجلا يعلمنا السنة والإسلام قال فأخذ بيد أبي عبيدة فقال هذا أمين هذه الأمة
Both of them (Bukhari and Muslim) narrated the hadith of Shubah from Abu Ishaq from Silah from Huzaifa, the story of the coming of the people of Najran, which contains the words, "He would certainly send a trustworthy man." Muslim added that Thawri narrated it from Abu Ishaq in a similar manner. He said, Israel narrated it from Abu Ishaq from Silah from Abdullah bin Masud, but Israel's version is not established as reliable.