How sound is the Hadith: "If heresies appear in my Ummah, then upon the scholar it is to make manifest his knowledge, and if he does not do so, then upon him be the curse of Allah, the angels, and all of mankind"?

The hadith: "If innovations appear and my Companions are cursed, then the scholar must manifest his knowledge. If he does not do so, then upon him is the curse of Allah, the angels, and all people." Its chain of narration is weak and not authentic, for Muhammad ibn Hayṣam and Ḥammād ibn al-Mubārak are unknown. He was followed by Muhammad ibn ʿAbd al-Majīd al-Tamīmī, who is weak, and Muhammad ibn ʿAbd al-Raḥmān ibn Raml, who is unknown.

This hadith was also narrated through another chain from Jābir with the wording: "If the latter part of this Ummah curses its former part, then whoever conceals a hadith has concealed what Allah has revealed." This chain of narration is very weak. Al-Albānī ruled the aforementioned hadith of Muʿādh as "munkar" (denounced).