Mukhtasar Bukhari

Narrated by Sayyiduna Hudhaifah (may Allah be pleased with him): Two chiefs of Najran, ‘Aqib (Abdul-Masih) and Sayyid (Ayyham), came to the Messenger of Allah (peace and blessings be upon him) with the intention of Mubahalah (mutual invocation of Allah’s curse). (The narrator) says that one of them said to the other, “Do not engage in Mubahalah, because if he is a Prophet and we do Mubahalah with him, by Allah, neither we nor our descendants after us will ever prosper.” Then both of them submitted, “Whatever you demand from us, we will continue to pay, so please send with us a trustworthy person, and do not send with us anyone except an honest (trustworthy) person.” The Prophet (peace and blessings be upon him) replied, “I will send with you a trustworthy person who is truly trustworthy.” The Companions of the Messenger of Allah (peace and blessings be upon him) began to look around (to see who would go). Then the Prophet (peace and blessings be upon him) said, “O Abu ‘Ubaidah ibn al-Jarrah! Stand up.” When he stood up, the Prophet (peace and blessings be upon him) said, “This is the trustworthy (reliable and honest) person of this Ummah.”

In one narration, Sayyiduna Anas (may Allah be pleased with him) reports from the Noble Prophet (peace and blessings be upon him) that the Messenger of Allah (peace and blessings be upon him) said: "Every nation has a trustworthy (reliable) person, and the trustworthy one of this nation is Abu Ubaidah ibn al-Jarrah."