We were sitting with the Prophet ﷺ when he said, "I do not know how long I will remain among you, so follow those who come after me," and he pointed to Abu Bakr and Umar, "take guidance from the way of Ammar, and whatever Ibn Masud tells you, accept it as true."
كنا جلوسا عند النبي ﷺ فقال: إني لا أدري ما قدر بقائي فيكم، فاقتدوا بالذين بعدي- وأشار إلى أبي بكر وعمر- واهتدوا بهدي عمار، وما حدثكم ابن مسعود فصدقوه.
Tirmidhi (3799), Ibn Majah (97), and Ahmad (23276, 23419) all narrated it through the route of Waki, from Sufyan (that is, Thawri), from Abdul-Malik bin Umayr, from a freedman of Rubai, from Rabi bin Harash, from Huzaifa, who then mentioned it. The freedman of Rabi bin Harash is named Hilal, as is made explicit in other routes. No one declared him trustworthy except Ibn Hibban, and for this reason Hafiz said, "Acceptable," meaning if corroborated, which is indeed the case, for he was corroborated by Amr bin Harm Azdi.This was narrated by Tirmidhi (3663), Ahmad (23386), Ibn Hibban (6902), and Tahawi in Sharh Mushkil (1233), all through the route of Salim Abu Ala Muradi, from Amr bin Harm, from Rabi bin Harash, from Huzaifa, who then mentioned it. Salim Muradi is Ibn Abdul-Wahid, whom Ibn Hibban mentioned among the trustworthy narrators. Tahawi said he was trustworthy, acceptable in narration. Ajli declared him trustworthy. Abu Hatim said, "His hadith is recorded," though Ibn Main and Nasai graded him daif. Nevertheless, he poses no problem when used for corroboration. Tirmidhi said this is a hasan hadith.This hadith was also narrated by Zaida bin Qudama, from Abdul-Malik bin Umayr, from Rubai, from Huzaifa, in similar wording. This was narrated by Tirmidhi (3662) and Ahmad (23245), but it is disconnected, for between Abdul-Malik bin Umayr and Rabi bin Harash lies the freedman of Rubai, as mentioned earlier in the narration of Thawri, and this is what Abu Hatim favored in Al-Ilal (2655).As for what was narrated from Anas bin Malik in marfu form, "The most merciful of my nation toward my nation is Abu Bakr, and the strictest of them in the matter of Allah is Umar...", the correct view is that it is mursal. See the details of this in the chapter on what has come regarding Abu Ubayda being the trustee of this nation.