Yoma, Chapter Six, Mishnah One
Most of this chapter deals with the goat whose lot was cast For Azazel that will be sent out into the wilderness. However, before the mishnah begins to deal specifically with that goat, it introduces the topic with some general laws concerning the acquisition of the two goats and what happens if one of the goats dies during the day.
1) The two goats of Yom Hakkippurim: it is a requirement that they be alike in appearance, in size, in value, and that they be bought at the same time.
a) But if they are not alike they are still valid.
b) If he bought one today and the other tomorrow, they are valid.
2) If one of them died before the lot was cast another one is bought for the second one.
3) But [if one of them died] after the lot was cast another pair must be bought and he must cast lots for them over again.
a) If the one that For Hashem died, he [the high priest] should say: This one upon which the lot For Hashem has fallen stands in its stead.
b) And if the one that was For Azazel died he should say: This one upon which the lot For Azazel has fallen stands in its stead.
4) The other one is left to pasture until it becomes blemished and it is to be sold and its value goes to the [chest for] voluntary offerings, for the sin-offering of the congregation is not be left to die.
a) Rabbi Judah says: it is left to die.
5) Furthermore Rabbi Judah said: if the blood was poured away, the goat which is to be sent away is left to die.
a) If the goat to be sent away died the blood is poured.
Section one: The mishnah teaches that the goats should be the same in appearance, cost the same and should be purchased the same day. In other words, they should be basically indistinguishable from one another. However, this is only a preferenceif they are not the same in appearance or they were not purchased on the same day, they are still valid.
Section two: The mishnah now discusses various scenarios in which one of the goats dies before it has served its ritual purpose. If one dies before the lots are cast, then the situation is easily remedied by purchasing a new goat.
Section three: The more complicated scenario is where one dies after the lots have been cast. In such a case they cannot just buy another goat, because that goat would automatically take the place of the old goat without it ever going through the lottery process. Rather they buy a new pair of goats and cast lots for them over again. Then the new goat takes the place of the lost goatif the goat For Hashem died, then the new goat which drew the lot For Hashem takes its place, and the same if the goat For Azazel died.
Section four: The mishnah now discusses what to do with the second goat of the new pair. This goat has no function because its place is taken by the living goat from the first pair. This goat has the status of a sin-offering (see Leviticus 16:5) that cannot be sacrificed. Usually a sin-offering that cannot be sacrificed is left to die. This situation arises when a person sets aside an animal to be a sin-offering, it is lost, he offers a new one in its place and then the old one is found. Such an animal is left to die. Our mishnah teaches that this is only true with regard to the sin-offering of an individual. The goat in our mishnah is communal and therefore it can go out to pasture until it becomes blemished, at which point it can no longer be sacrificed. Then it is sold and the proceeds go to the Temple.
Rabbi Judah disagrees and holds that just as an individually owned sin-offering that cant be offered is left to die, so too is a communally owned one.
Section five: The mishnah now points out that Rabbi Judah goes even further. If the blood of the goat For Hashem is spilled and therefore cant be used, and all the more so if the goat dies, the other goat designated For Azazel must die as well. Similarly, if the goat to be sent out to the wilderness dies, the blood of the other goat, the one For Hashem must be spilled out. If the For Hashem goat has not yet been slaughtered, it must be left to die. In other words, Rabbi Judah disagrees with the halakhah in section four which says that if one goat dies then the other may still be used. He holds that if one dies, the other dies as well. You might say that their lots are inextricably linked!