Temurah 16B

וכי דנין אפשר משאי אפשר? רבי שמעון בחד מקום גמיר להו.

The Talmud asks: But can one derive the possible from the impossible? Those other cases include offerings that by definition do not apply to a community; how can one learn from them with regard to cases where they are possible? The Talmud answers: R' Shimon learns this tradition as one unit, i.e., all the cases of sin offerings left to die are given as one halakha, and therefore there is no difference in their application.

אמר ריש לקיש: ארבעה נתנו להן, והעמידום על חמש. ואי סלקא דעתך בצבור ⁠— הנך מי איתנהו בצבור? אלא על כרחיך ⁠— ילמד סתום ממפורש.

Reish Lakish says in explanation of this matter: When Moses received this tradition at Sinai, the halakhot of 4 sin offerings that must be left to die were given to the Jewish people, whereas the fifth sin offering is left to graze until it develops a blemish. But as they did not know which of the sin offerings was the one that should be left to graze, they established these halakhot with regard to all 5 sin offerings, that they are all left to die. However, given that the 4 sin offerings were said together, either all 4 are communal sin offerings, or all 4 are sin offerings of the individual. And if it enters your mind that the 4 cases of sin offerings that must be left to die, as stated to Moses, referred to communal offerings, are all of these 4 sin offerings possible as communal offerings? Rather, the tradition is with regard to sin offerings of the individual. Rather, perforce one must derive the cases that are unspecified in terms of their halakhot from those cases that are specified.