Our daf opens with a baraita that records a disagreement between Beit Hillel and Beit Shammai. The topic of debate is pat ava – whether thick matza can be baked on the holiday of Pesah. Beit Hillel permits such baking to be done; Beit Shammai forbids it.
Rav Huna interprets the expression pat ava to be similar to the size of the lehem ha-panim – the showbread in the Temple – which was also matza and was one tefah (handbreadth) thick.
R Yosef objects to the comparison on a number of levels:
- We know that the kohanim in the Temple were quick about their work.
- The dough was always well-kneaded.
- The fire-wood in the Temple was always very dry.
- The ovens were very well heated.
- The ovens in the Temple were made of metal, not clay.
Given the severity of the prohibition against eating hametz, and the difficulty involved in baking thick matza properly, even if it was done in the Temple for the lehem ha-panim, how can Beit Hillel permit it on Pesaḥ for the general public?
In explanation of this baraita, one suggestion that is raised (either by Rav or by Rabbi Yehuda haNasi) is that pat ava does not mean to bake a thick cake; rather it means to bake a large amount at one time. The Gemara points out that if we understand pat ava this way, the potential problem would not be specific to Pesaḥ, but it is a general issue of possibly baking unnecessarily on Yom Tov.
Rabbenu Yehonatan explains that if this is, in fact, the point of disagreement, Beit Shammai forbids it lest some of the bread or matza will be left over and will be used after Yom Tov is over, creating a situation where preparations for the regular weekday were done on the holiday. Beit Hillel would argue that the baking process works better when a large amount is baked, so having leftovers is of no concern.