The Prophet ﷺ said, "It does not befit a two-faced person to be trustworthy."
حدثنا عبيد بن أبي قرة حدثنا سليمان عن ابن عجلان عن عبيد الله بن سلمان الأغر عن أبيه
أن النبي ﷺ قال ما ينبغي لذي الوجهين أن يكون أمينا
Its chain of transmission is sahih. Sulayman is Ibn Bilal. Ibn Ajlan is Muhammad. Ubaydullah bin Salman Aghar is trustworthy, Ibn Main and others declared him trustworthy, and Bukhari cited him in his Sahih. Ibn Abu Hatim gave his biography at 2/2/316. In the three source manuscripts here, his father's name appears as "Sulayman," as it also appears in the hadith before this one, but this is undoubtedly an error. The correct reading is confirmed in Jami al-Masanid. His father is Salman Abu Abdullah Aghar. The phrase "from his father" has dropped out of the three source manuscripts here, and we have added it from Jami al-Masanid and from what will come later in the sourcing.Furthermore, this Ubaydullah does not narrate from any of the companions, in fact no narration is recorded for him except from his father. This hadith will come at 8767 through Khuzai, from Ibn Bilal, from Ibn Ajlan, from Ubaydullah bin Salman Aghar, from his father, from Abu Hurairah, which is the correct version. Bukhari also related it in Adab al-Mufrad, pages 47-48, from Khalid bin Mukhlad, from Sulayman bin Bilal, with this same chain, correctly, with the wording "it is not fitting" instead of "it is not fitting" (with a different Arabic word for the same meaning). Hafiz mentioned it in Fath al-Bari, 10:396, citing the narration from Adab al-Mufrad. See also 7337.