8 - ʿUmar ibn al-Khaṭṭāb. in "al-Mustadrak" (4/449), which he authenticated and al-Dhahabī agreed with him. Thus, the ḥadīth is certainly authentic, and I have only mentioned it for the sake of this addition. You have already known that its chain to Yazīd ibn Hārūn is weak, and with this isnād, it was narrated by Abū Bakr al-Khaṭīb in his book "Sharaf Aṣḥāb al-Ḥadīth" (Q/34/1). Al-Ḥāfiẓ attributed it in "al-Fatḥ" (13/249/Būlāq) to al-Ḥākim in "ʿUlūm al-Ḥadīth," and I think this is only an error, for I have searched for it there and did not find it. I only found what comes from Imām Aḥmad. However, this addition is known and established from a group of the people of ḥadīth from the generation of Yazīd ibn Hārūn and others. They are: 1 - ʿAbd Allāh ibn al-Mubārak (118 - 181), as al-Khaṭīb narrated with his isnād from Saʿīd ibn Yaʿqūb al-Ṭālaqānī or someone else who said: "Ibn al-Mubārak mentioned the ḥadīth of the Prophet (ṣallá Allāhu ʿalayhi wa-sallam): 'A group will always remain...' Ibn al-Mubārak said: 'They are, in my view, the people of ḥadīth.'" 2 - ʿAlī ibn al-Madīnī (161 - 234), and al-Khaṭīb also narrated through al-Tirmidhī, and this is in "Sunan" (2/30). He has cited the ḥadīth from the narration of al-Muzanī mentioned earlier (number 5) and then said: