Why the She-Goat Sin Offering Must Be a Yearling

"And he shall bring his offering, a she-goat of the goats" (Leviticus 4:28) - from where do we learn that he brings one in its first year? It is a logical inference: this one brings a sin offering and the leper brings a sin offering; just as the leper's sin offering is in its first year, so too this one is in its first year. No - if you said this of the leper's sin offering, which requires libations, would you say it of this one, which does not require libations? The nazirite's sin offering proves it, for it does not require libations and yet comes in its first year. No - if you said this of the nazirite's sin offering, which has other blood [offerings] with it, would you say it of this one, which has no other blood with it? The sin offering for idolatry proves it, for it has no other blood with it and yet comes in its first year. No - if you said this of the sin offering for idolatry, which is fixed [obligatory], would you say it of this one, which is not fixed; since it is not fixed, perhaps it does not come in its first year? The verse teaches "one law shall there be for you for him who does anything in error" (Numbers 15:29) - thus everyone who acts in error is like idolatry: just as the sin offering for idolatry is in its first year, so too this one is in its first year. If so, just as the sin offering for idolatry is a she-goat - when it says "for you," it comes to include the goats for idolatry; "for you" to include the goats of the festivals; "for him who does" to include the goat of the prince.