Aqib and Sayyid, the two leaders of Najran, came to the Messenger of Allah ﷺ intending to invoke a mutual curse with him. One of them said to his companion, "Do not do it. By Allah, if he is truly a prophet and we engage in mutual cursing with him, neither we nor our descendants after us will ever prosper."They said, "We will give you what you have asked of us. Send with us a trustworthy man, and send with us only one who is trustworthy."He replied, "I will indeed send with you a man who is truly trustworthy."The companions of the Messenger of Allah ﷺ each hoped to be chosen. Then he said, "Stand up, Abu Ubayda bin al-Jarrah."When he stood, the Messenger of Allah ﷺ said, "This is the trustworthy one of this nation."
جاء العاقب والسيد صاحبا نجران إلى رسول الله ﷺ يريدان أن يلاعناه، قال: فقال أحدهما لصاحبه: لا تفعل، فوالله لئن كان نبيا فلاعنا لا تفلح نحن ولا عقينا من بعدنا. قالا: إنا نعطيك ما سألتنا، وابعث معنا رجلا أمينا، ولا تبعث معنا إلا أمينا، فقال: لأبعثن معكم رجلا أمينا حق أمين، فاستشرف له أصحاب رسول الله ﷺ، فقال: قم يا أبا عبيدة بن الجراح، فلما قام، قال رسول الله ﷺ: هذا أمين هذه الأمة.
Bukhari narrated it in the Book of Military Expeditions (4380) from Abbas bin Husayn, who said, Yahya bin Adam narrated to us, from Israil, from Abu Ishaq, from Salah bin Zafar, from Huzaifa, who mentioned it.