Clarification: It seems to the Riva that other nights too, require a Ribuy ...

Reason: Because the Pasuk "u'Semachtem Lifnei Hash-m Shiv'as Yamim", from which we learn Shalmei Simchah, we also Darshen from it in Perek Lulav va'Aravah (Succah 43.) that Lulav applies seven days in the Beis-ha'Mikdash, and that Din is confined to daytime only.

Conclusion: Only the last night of Yom-Tov requires it even more, since the eighth day is an independent Yom-Tov ...

Conclusion (cont.): And we would have thought that one is not obligated to Shecht Shalmei Simchah on the seventh day to eat on the night of the eighth any more than one obligated to Shecht on Erev Yom-Tov to eat on Yom-Tov.

Clarification: In which case it comes, not to preclude other nights, only the last nights.

Question: Why do we not learn this from the other Pasuk ("Vezavachta ... Vesamachta") from which we learn that one needs to Shecht at the time of Simchah?

Answer: From that Pasuk, we would have thought that one only needs to Shecht at the time of Simchah with regard to the Shalmei Chagigah of Yom Tov (which was slaughtered on Erev Yom Tov and is being eaten the following day to be Yotzei Simchah, see 70b and Tosfos there), since it is possible to Shecht it on Yom Tov itself...

Answer (cont.): Whereas here, where one cannot Shecht it at nighttime, it is not necessary.

Conclusion: Hence one needs "Ach" to preclude it.

Explanation #1: Rashi explains that this refers specifically the nighttime, but not to the day.

Question: The Riva queries this however, from the Mishnah, which states that 'Hallel and Simchah apply for eight days'.

Refuted Answer: And one cannot answer that it says 'eight' on account of the night ...

Refutation #1: Since bearing in mind that it does not include the first night is not included, there are not eight nights.

Refutation #2: Moreover, it Hallel, which one recites by day.

Refutation #3: Furthermore, when the Gemara asks later on 'And if one holds ... , it sometimes transpires that there are not eight days - i.e. when the first day falls on Shabbos!' ...

Refutation #3 (cont.): According to Rashi, one could ask the same question according to all opinions - where the eighth day falls on Sunday, where there will only be seven days ...

Reason: Because when will one be able to Shecht for the night of the eighth which then falls on Motza'ei Shabbos?

Reason (cont.): Since, if one were to Shecht it on Erev Shabbos, it would be Pasul!

Explanation #2: One therefore needs to explain that the night of the last day is La'v Davka, and that it includes the day.

Clarification: It is from here that we learn the Eimurin of all Korbanos.

Question: The Ri asks from a Beraisa at the end of Perek Kol ha'Pesulim (Zevachim, Daf 36.) which learns from the Pasuk "u'Vesar Zevach Todas Shelamav" that the Todah can be eaten for a day and a night.

Question (cont.): And it goes on to learn Shalmei Nazir and Shalmei Pesach from the word "Shelamav".

Question (cont.): And Rashi there interprets 'Shalmei Pesach' as the Chagigah of the fourteenth.

Question (concl.): Now like whom does that Beraisa hold? Seeing as according to the Tana in our Sugya, it can be eaten for two days, and even ben Teima (above on Daf 70.), according to whom it can be eaten for only a day and a night, learns it from the comparison to Pesach, whereas there (in Zevachim) the Tana learns it from "Zevach Todas Shelamav"?

Answer: Therefore the Ri explains that 'Shalmei Pesach' which the Tana there mentions, refers to the leftover Pesach which is brought as Shelamim.

Proof: Now it fits very well, since the Gemara later in Perek ha'Ishah (Daf 89.) states say that the leftover Pesach is eaten for only a day and a night. Now from where does it know this if not from the Pasuk there ("Shelamav")?

Support: Indeed the Toras Kohanim in Parshas Tzav es Aharon specifically supports the Ri ...

Support (cont.): When it Darshens there "u'Vesar Zevach Todas Shelamav" with reference to Shalmei Pesach ...

Support (cont.): After which it cites our Sugya, and learns from "Lo Yalin min ha'Basar asher Tizbach ba"Erev" that the Chagigah that is brought together with the Pesach can be eaten for two days and one night.

Conclusion: So we see that the Shalmei Pesach mentioned above refers to the leftover Pesach that is brought as a Shelamim.

Question: The Rashba asks that, since the entire Pasuk speaks about the Chagigah of the fourteenth, and "Boker" refers to the second morning, why can it not be eaten for two days and two nights ...

Conclusion: Seeing as the Pasuk implies that it does not become Pasul until the second morning, and that it can be eaten on the eve of the second day.

Question: The Ri queries this from the end of 'Arvei Pesachim', where the Gemara Darshens "Boker" to mean the second morning, even though it is written S'tam?