Hello again.
The Gemora discusses the Asseh of Korban Pesach overriding the Asseh of Hashlamah.
But can Reuven's Asseh be Doche Shimon's Asseh? (It is the Kohen who is Metzuveh in Hashlamah )
If it was a case of Asseh Doche Lo S'Asseh we wouldn't say that 1 person's Asseh is Doche another person's Lo S'Asseh. Or would we?
Thank You,
Jeno Gal
Dear Jeno,
(a) Rebbi Akiva Eiger brings Tosfos Shabbos 4a DH v'Chi who discusses your question.
The Gemara in Shabbos 4a states that a person cannot sin a small sin in order to save his friend from transgressing a big sin. Why then can the Kohen transgress the prohibition of Hashlamah to help his fellow Jew bring a Korban Pesach?
Tosfos answers that it is forbidden to transgress a prohibition in order to save another person from transgressing when the other person is at fault in some way. However when the other person is not to blame for his predicament (as with the case of Korban Pesach), it is permitted and expected for others to transgress a lesser prohibition in order to prevent him from transgressing a greater prohibition. That is why the Kohen is allowed to transgress the Aseh of Hashlamah (a simple Aseh) in order to help another Jew fulfill the Aseh of bringing a Korban Pesach (an Aseh associated with Kares).
(b) Regarding Aseh Docheh Lo Sa'aseh - see the Aruch la'Ner in Yevamos 20a DH Yavo who discusses this matter at length.
However, that question need not be related to our Gemara. A Lo Sa'aseh is normally a stronger prohibition than an Aseh, and nevertheless the Aseh overrides it through a Gezeiras ha'Kasuv (Yevamos 9a). If so, that same Gezeiras ha'Kasuv might explicitly permit the Lo Sa'aseh on the part of both parties involved, even if the Aseh only applies to one of the two.
All the best,
Reuven Weiner