The origin of any law is either Biblical or rabbinic. If the latter, it may be early or late. There are many gaps in the collective recollection of origins, and questions arise as to whose opinion is being cited and whether or not it was derived by the same reasoning by every scholar who holds it to be correct. The answer to even the most simple question may lead to extensive discussion because the simple answer to one question may create complications when a similar case is raised in a different context.
Can we get benefit from chametz once it is forbidden to eat it? Another six dapim later, and we seem to be no closer to an answer, despite a seemingly clear Mishnah (21a).
Daf 341 (Pesachim 18a-18b)
R’Yose is cited as saying that beverages have the Biblical capacity to contaminate. Reish Lakish insists that R’Yose himself does not hold this opinion but is only quoting his teacher (Akiva). The rabbis argue exactly what materials might be contaminated by beverages– food, utensils, other beverages?
Daf 342 (Pesachim 19a-19b)
Whether or not R’Yose agrees with Akiva remains unresolved, but it is clearly established that in at least one instance Akiva does not agree with R’Yose.
Do rabbinic rules regarding contamination of hands apply in the Temple? There is a question of when the rabbinic decree was enacted. (Was there still a Temple?)
Daf 343 (Pesachim 20a-20b)
How many steps are there in diminishing degrees of contamination? This is the subject of detailed dispute in this daf before the focus finally returns to the question of whether chametz that is possibly tamei may be burned with chametz that is definitely tamei. Another question interrupts the deliberations: Should one take action “out of concern for the commission of a misdeed”?
Daf 344 (Pesachim 21a-21b)
Perek 2. Mishnah. It is permitted to benefit from chametz (e.g., use it as animal feed or sell it to a gentile) for as long as it is permitted to eat it.
Gemara. The gemara seeks to determine which rabbi’s view is in accordance with the mishnah. This leads to a consideration of whether giving it to a “stranger” should take precedence over selling it to a “heathen”: “Since you are anyway commanded to sustain a stranger and you are not commanded to sustain a heathen . . . it is a rational conclusion!”
Daf 345 (Pesachim 22a-22b)
The rabbis seek to determine when it is permitted to derive benefit from objects that are otherwise forbidden to their owner.
Daf 346 (Pesachim 23a-23b)
In a baraisa, R’Yose Haglili asks, “How can you say that chametz is forbidden for benefit all seven days of Pesach?” The meaning of this question is vigorously debated.
R’Yehudah and R’Chizkiyah agree that it is forbidden to benefit at all from chametz when it is forbidden to eat it (or from an ox to be stoned), but they do not reach the conclusion through the same reasoning. The gemara seeks to uncover the implications of the different reasonings to anticipate how each rabbi might rule on other matters.