The Aqib and the Sayyid, the two leaders of Najran, came to the Messenger of Allah ﷺ, intending to engage him in mutual imprecation. One of them said to his companion, "Do not invoke a curse with him, for by Allah, if he is truly a prophet and we curse him," (Khalaf said the wording was, "If we curse him,") "neither we nor our descendants will ever prosper."So they came to him and said, "We will not engage in mutual imprecation with you. Instead, we will give you what you have asked. Send with us a trustworthy man."The Prophet ﷺ said, "I shall surely send with you a man who is truly trustworthy, truly trustworthy."The companions of Muhammad eagerly hoped to be chosen for this task. He said, "Stand up, Abu Ubayda bin al-Jarrah."When he turned to leave, the Prophet ﷺ said, "This is the trustworthy one of this nation."
حدثنا أسود قال وأخبرنا خلف بن الوليد حدثنا إسرائيل عن أبي إسحاق عن صلة
جاء العاقب والسيد صاحبا نجران قال وأرادا أن يلاعنا رسول الله ﷺ قال فقال أحدهما لصاحبه لا تلاعنه فوالله لئن كان نبيا فلعنا قال خلف فلاعنا لا نفلح نحن ولا عقبنا أبدا قال فأتياه فقالا لا نلاعنك ولكنا نعطيك ما سألت فابعث معنا رجلا أمينا فقال النبي ﷺ لأبعثن رجلا أمينا حق أمين حق أمين قال فاستشرف لها أصحاب محمد قال فقال قم يا أبا عبيدة بن الجراح قال فلما قفا قال هذا أمين هذه الأمة
Its isnad is sahih. Sila is Ibn Zufr Absi. As for his statement at the beginning of the isnad, "Aswad narrated to us," followed by, "and Khalaf informed us," this is how it appears in both original manuscripts, but the intended meaning is not its apparent one. What is meant is that the Imam narrated it from Aswad bin Amir and from Khalaf bin Walid, both of them from Israil. This is supported by his statement in the course of the hadith, "Khalaf said, 'Then he called us to a mutual curse,'" which indicates that he narrated it from his two teachers, Aswad and Khalaf, since one of them had narrated from the other.Sila ibn Zufr also narrated this hadith from Huzaifa bin Yaman, so he heard it from both companions, Huzaifa and Ibn Masud, and he narrated it sometimes from one and sometimes from the other.Ibn Kathir quoted it in his Tafsir, 2/156, from Bukhari, from the hadith of Sila from Huzaifa, then said, "Bukhari, Muslim, Tirmidhi, Nasai, and Ibn Majah narrated it from the hadith of Israil, from Abu Ishaq, from Sila, from Huzaifa, in similar wording." Ahmad, Nasai, and Ibn Majah also narrated it from the hadith of Israil, from Abu Ishaq, from Sila, from Ibn Masud, in similar wording.Ibn Kathir mentioned the story of Najran in detail in that same place, and Ibn Saad mentioned it in Tabaqat, 1/2/84-85.