The Peak of Eloquence · Hadith 1297 (#Passage #106)

وَإِنَّ أَعْظَمَ الْخِيَانَةِ خِيَانَةُ الْأُمَّةِ، وَأَفْظَعَ الْغِشِّ غِشُّ الْأَئِمَّةِ، وَالسَّلَامُ.

Surely, the greatest treachery is the treachery against the Muslim community, and the ugliest deceit is the deceit towards the Muslim leaders; and that is an end to the matter.

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).