Inferred Halachah: Some commentaries extrapolate from here a prohibition on the self-imposed Niduyim that people tend to take upon themselves nowadays, even if they are time-bound.

Refutation: This is not correct however. The condition that Yehudah made was not in his power to fulfill (seeing as there was nothing he could have done had Yosef held him back or had some other accident occurred on the journey). But Niduyim which people place on a person not to do this or that, which basically lie in his power to fulfill, the Niduy is ineffective to begin with (seeing as we know in advance that he has no intention of carrying out the condition).

Question: The Midrash explains that when Reuven returned to the pit (to retrieve Yosef from it and bring him back to his father), he had come from his father's house, where he spent the day fasting to atone for the episode with Bilhah; and this took place many years before the incident discussed in our Sugya?

Answer: True, Reuven had done Teshuvah already then, but he did not admit his sin publicly until the incident with Yehudah.

Proof: We have a proof for this from Unklus, who translates the Pasuk in Vay'chi "Yehudah, your brothers will thank you" as 'You confessed and were not ashamed, so your brothers will thank you'. Because, due to the fact that you began to confess, Reuven too, came and confessed' (see Mesores ha'Shas).

Question: Using the same 'Kal-va'Chomer', why can we not learn that a murderer whose Din is completed without a Kohen Gadol, is Patur from Galus, on the grounds that, if someone who has already been exiled before the Kohen Gadol's death, goes out when he dies, someone who has not yet gone into Galus when he dies, should certainly not go into exile!?

Proof: And we have a precedent for this in Arachin (Daf 20b & 30a) where the Gemara prohibits selling a twelve-year old girl with a 'Kal-va'Chomer', on the grounds that if she is already working she goes free when she turns twelve, how much more so does she not go in!

Answer (and Refutation): It seems that there is no comparison between our case and the case in Arachin. In our case, the death of the Kohen itself serves as a Kaparah (as we will see shortly) in which case it will atone for someone who requires a Kaparah. Consequently, someone whom Beis-Din declared Chayav to go into Galus, who requires a Kaparah, is Patur from Galus from a 'Kal-va'Chomer', should the Kohen Gadol die before he has a chance to go into Galus. Whereas in our case, where the Kohen Gadol died before his Din was concluded, in which case he was not yet Chayav to go into Galus, one cannot learn a Kal va'Chomer - because how can the death of the Kohen Gadol atone?

Suggested Answer: Why can we not answer that when the Din is concluded, the death of the Kohen Gadol should atone retroactively?

Refutation: That answer is unacceptable, since the Kohan Gadol's death only atones at the time of death (but not afterwards), and at the time of death, he was not yet Chayav.

A Different Criterion: The case in Arachin of 'Mechurah K'var Yotz'ah ... ' is quite different, inasmuch as there the moment she produces signs of puberty, her adulthood begins and is not subject to change. Consequently, we can learn via a 'Kal-va'Chomer' that she can never be sold, once those signs have appeared (so it appears to Mashi'ach).

Question: Indeed Galus atones, as we said at the beginning of the Masechta 'They, who did not perform an act, should go into Galus, in order that they should have a Kaparah'?

Answer: The Kaparah here (unlike the Kaparah mentioned on Daf 2) refers to exempting the murderer from Galus, as is evident from the fact that we try to learn that the death of the Kohen Gadol will exempt someone who has not yet gone into Galus from the need to go.

Conclusion: That is why the Gemara correctly answers 'Is Galus Mechaper? The death of the Kohen Gadol is Mechaper!' After all, even if the Kohen Gadol dies after he has spent only one day in exile, he goes free; whereas if the Kohen Gadol would not die for a long time, he would not go free. Clearly then, this Kaparah is dependent upon the Kohen Gadol's death (so it appears to Mashi'ach).