The gemara has two suggestions for a general derivation of issur hana'a, based on the obligation to burn a particular sacrifice. Since the verse is viewed as redundant, the gemara suggests using the principle of "im eino inyan" to derive a general issur hana'a for all issurei akhila.
The gemara on 24b brings two variants of a statement of R. Abahu, limiting the liability in cases of issur. We shall first examine Rashi's understanding of these two statements (especially in light of the commentary of R. David), and the analyze the opinion of the Rambam.
The gemara introduces a new topic - hana'a she-ba'a le-adam baal korcho. Obviously the term "baal korcho" does not mean totally under duress, for then there would not be anything to talk about. If one was compelled by force to have forbidden hana'a, then what is done is done, and in any event, "oness rachmana patrei" (one is not culpable for actions performed under duress). The gemara divides the case into four.
We will be discussing various points raised in the different cases the gemara cites on 26a as proofs of either Rava's or Abaye's position. This will help us clarify the concept of hana'a haba'a l'adam baal korcho, as well as a number of other points. One thing to watch out for - when Abaye or Rava bring a proof, is it to the first or second version (on 25b) of their positions?