Chabad.org — English translation + Rashi
Torah Temimah points to Horayos 5b (unit 4; single primary locus per emergency Core plan).
E-Daf.com — Horayos 5b
HebrewBooks / Shas PDF
English: “And the assembly shall offer” — if one tribe sinned it also brings a bull; why? One tribe is also called “kahal.”
Single tribe as kahal — a single tribe that follows an erroneous ruling brings its own communal-style bull.
Even one shevet that follows an erroneous hora’ah of the Sanhedrin is obligated to bring a bull. The verse’s use of “kahal” is understood to apply to a single tribe as well as to the nation as a whole. The liability tracks the actual scope of the action that was taken on the basis of the mistaken ruling.