I know it is a bit early, but I wanted to share some marei mekomos I came across last year in the Mesifta Hagada.
first a recap, the discussion began about size of a “kezayis” and somebody brought the obligatory kvetching about how hard it is to eat modern day “kezaysim”.
I pointed out strictly mesevara that the discussion regarding size of “kezayis” always struck me as starnge, since a kezayis is the MINIMUM amount needed to be considred an achila. It isnt a goal to strive/struggle towards. There is something wrong with the sizing if eating a kezayis is a struggle for a normal person.
I maintained that the Mitzva is eating matza period. As all mitzvahs there are techinical (sometimes critical) halachas, minimum shiur: kezayis, maximum shiur: Achila Gasa, time frame: Kedei achilas pras etc etc.
I didnt bring any rayahs since this seemed obvious to me. There is no Gemara that brings a limud how much Matza needs to be eaten, like any achila (both mitzvos and issurim), any less that a kezayis simply isnt called eating.
DY and Sam2 pointed out that the implication of my statment is that there is a mitzva/hidur of some sort to eat more than a kezayis a notion they disagreed with.
Here are some marei mekomos:
Rambam 6:1 is mashma this way. He says “there is a mitzvas aseh to eat matza period (literaly)…once a person has eaten a kezayis he is yotzeh yedei chovoso” He does not say There is a mitzva to eat a kezayis matza.
(Diyuk brought in moadim uzemanim)
Bach brings besehm Maharl that all eating matza leshem mitzva is part of the mitzvah.
Kehilas Yaakov kidushin siman 34 brings the same idea besehm the shiltos and brings many raayas (Its actually a very nice read, though I dont own a kehilas yaakov so i havent seen it in a while now)