Siman - Pesachim Daf 102

• הניחו מקצת חברים

It  was taught in a Baraisa, חברים שהיו מסובין  - Chaveirim who were reclining (i.e. dining) together, ועקרו רגליהם לילך לבית הכנסת או לבית המדרש – and they uprooted themselves to go to the beis haknessess or to the beis hamedrash, when they leave they are not required to recite a berachah acharonah on what they had previously eaten, and when they return they are not required to recite a berachah rishonah before continuing to eat. Rebbe Yehudah said, when are these words said? בזמן שהניחו שם מקצת חברים  - When they left some chaveirim there. But if they disbanded completely and did not leave some chaveirim there, when they leave they are required to recite a berachah acharonah on what they had previously eaten, and when they return they are required to recite a berachah rishonah before continuing to eat.

• אין עושין מצוות חבילות חבילות

We  learned on Daf 100a, that according to Rebbe Yose, someone who was eating a meal when it became Shabbos may continue to eat, without interrupting for Kiddush. Here, the Gemara cites a Baraisa that teaches that according to Rebbe Yose, when the person eventually finishes his meal, he should say Bircas Hamazon over one cup of wine and then Kiddush over another.

The Gemara asks why Bircas Hamazon and Kiddush cannot both be said over the same cup. Rav Nachman bar Yitzchak explains: לפי שאין עושין מצות חבילות חבילות – Because we do not do mitzvos in bundles. Rashbam explains that someone who does this indicates that mitzvos are burdensome for him.

The Gemara challenges this based on a Baraisa that teaches that someone who does not have a second cup of wine, should say Bircas Hamazon and Havdallah on the same cup. The Gemara answers: אין לו שאני – [A situation in which] he does not have [a second cup] is an exception to the general rule that mitzvos should not be performed in bundles.

• הבדלה וקידוש חדא מילתא היא

The Gemara continues to challenge the above rule, noting that (as will be discussed at length just below) when Yom Tov falls on Motzei Shabbos, Kiddush and Havdalah are said over the same cup of wine, even on the first night of Yom Tov, when one certainly has more than one cup of wine. Rashbam explains that the assumption that one has multiple cups of wine on the first night of Yom Tov is based on the Mishnah, which taught that even the poorest Jew must be given four cups of wine on the first night of Pesach.

The  Gemara answers: הבדלה וקידוש חדא מילתא היא – Havdalah and Kiddush are one thing, so there is therefore nothing wrong with saying both of these over a single cup of wine. Rashbam explains that both Havdalah and Kiddush are based on the holiness of the Yom Tovim, and the holiness of the incoming   Yom  Tov is even mentioned in the wording of Havdalah.