Musaf: Who brought a goat to the party?

And at the beginnings of your months you shall offer to God an elevating-offering: two young bullocks and one ram, yearling lambs seven in number, without blemish. And their gift of tribute and their drink offerings as declared: three tenths for each bullock, two tenths for the ram, and one tenth for each lamb, and wine like its drink offering and one he-goat for atonement and and two regular offerings according to their rule.

[All of the following:]
a) the offspring of [an animal designated as] a sin-offering,
b) an animal exchanged for [an animal designated as] a sin-offering,
c)[an animal designated as] a sin-offering whose owner dies, and
d) such animal that was lost and then found only after the owner secured atonement, should be consigned to die. ...
All of these matters were conveyed by Moses our teacher.
All of the above applies only to a sin-offering designated by an individual. [An animal designated as] a communal sin-offering, by contrast, which was lost and then discovered after atonement was secured - whether it is fit [to be offered as a sacrifice] or unfit- should be left to pasture until it contracts a blemish and then sold. The proceeds should be used for freewill offerings. With regard to communal sin-offerings, it is impossible to speak of offspring, exchanges, or the owners dying, because all of the communal offerings are male. The community cannot exchange one sacrificial animal for another as will be explained. And the entire Jewish people will not die.

And in the beginnings of your months you shall offer a burnt offering to the Lord; two young bullocks, and one ram, seven lambs of the first year without blemish; and three tenth measures of flour for a meal offering, mingled with oil, for one bullock; and two tenth measures of flour for a meal offering, mingled with oil, for one ram; and a tenth measure of flour mingled with oil for a meal offering for every lamb; for a burnt offering of a sweet savour, a sacrifice made by fire to the Lord. And their drink offerings shall be half a hin of wine for a bullock, and the third part of a hin for a ram, and a fourth part of a hin for a lamb: this is the burnt offering of every month throughout the months of the year. And one kid of the goats for a sin offering to the Lord shall be offered, beside the continual burnt offering, and its drink offering.

§ The mishna teaches: For the defiling of the Temple or its sacrificial foods in which one did not have awareness, neither at the beginning nor at the end, the goats brought as sin-offerings as part of the additional offerings of the Festivals and the goats brought as sin-offerings as part of the additional offerings of the New Moons atone. This is the statement of Rabbi Yehuda. The Gemara elaborates: Rav Yehuda says that Shmuel says: What is the reasoning of Rabbi Yehuda? The verse states with regard to additional offerings of the New Moons: “And one goat for a sin-offering to the Lord” (Numbers 28:15). The final phrase, which literally means: A sin to the Lord, alludes to the fact that this goat atones for a sin of which only the Lord is aware, i.e., where there was no awareness either at the beginning or at the end. The Gemara objects: But this phrase is necessary in order to expound it in accordance with the statement of Reish Lakish, as Reish Lakish says: What is different about the goat brought as a sin-offering of the New Moon that it is stated with regard to it: “To the Lord,” a term not written with regard to other sin-offerings? The Holy One, Blessed be He, says, as it were: This goat shall be an atonement for the fact that I diminished the size of the moon.

Rabbi Ishmael his son said: He who learns in order to teach, it is granted to him to study and to teach; But he who learns in order to practice, it is granted to him to learn and to teach and to practice. ...