Pesahim 69a and Pesahim 69b, figuring out R, Eliezer’s position on allowing makhshirei mitzvah, needed adjunct elements of a mitzvah being performed on Shabbat, and who counts or does not count as relevant to the Pesah sacrifice (and therefore possibly liable for failure to bring it), R. Akiva’s position that only those makhshirin we could not have done before Shabbat may be done on Shabbat and then a beginning of the discussion of hagigat 14, the sacrifice brought along with the Pesah to make sure the Pesah is eaten while full.
