Levítico 4:14 Midrash: Sifra & Sifrei Bamidbar

12) (Vayikra 4:14): ("If the sin became known wherein they have sinned"): If it became known (to the people) that beth-din had ruled erroneously (in respect to one of two acts, both of which they later performed on their ruling); but they could not ascertain in which ruling they had erred — I might think that they would (nevertheless) be liable (for a sin-offering, knowing, at least, that they had acted on an erroneous ruling of beth-din); it is, therefore, written: "If the (specific) sin became known," and not: "If the sinners became known."

13) "… wherein they have sinned, then the assembly shall offer, etc.": If two tribes sinned, they bring two bullocks; if three tribes sinned, they bring three bullocks. — But perhaps the meaning is that two sinners (in an assembly of sinners) bring two bullocks; three sinners bring three bullocks (i.e., each one in the assembly brings a bullock). It is, therefore, written: "the assembly (shall offer"). The assembly (and not each individual) is liable, (one bullock for the entire assembly), and each assembly (i.e., tribe) is liable (for itself).

14) How so? If two tribes sinned, they bring two bullocks. If three tribes sinned, they bring three. And the other tribes, which did not sin, bring a bullock (each) because of them. For even those who did not sin bring because of the sinners. These are the words of R. Yehudah.