Parashas Masei · Passuk 35:16 · TT note 2
Chabad.org — English translation + Rashi
Torah Temimah points to Chullin 11b (TT note on “מוֹת יוּמַת”).
English: From where do the Sages derive “follow the majority”? Rav Kahana said: it is derived from one who kills a person — the Merciful One said kill him, yet perhaps [the victim] was a treifah; rather, is it not because we say follow the majority?
Scriptural source for the principle of following the majority (rov).
The death penalty for a murderer proceeds even though the victim might theoretically have been a treifah; the law follows the majority of viable people.