- The reasons behind the machlokes of חצי שיעור
The Gemara on Daf 73b introduced a machlokes between Rebbe Yochanan and Reish Lakish regarding חצי שיעור. The Gemara here explains their reasoning. Rebbe Yochanan says that it is assur min haTorah כיון דחזי לאיצטרופי איסורא קא אכיל – since the חצי שיעור he now eats is fit to combine with more of the same forbidden food to complete the full shiur. Reish Lakish says that it is mutar min haTorah אכילה אמר רחמנא וליכא – for the Torah stated that “eating” certain foods is prohibited, and when eating a חצי שיעור there is no halachic act of "eating". Only the consumption of a kezayis of food constitutes an act of eating.
- תענו את נפשתיכם does not apply to sitting in the sun or shade
It was taught in a Baraisa: The Torah states that on Yom Kippur "תענו את נפשתיכם" – you shall afflict yourselves. It could be thought that this means that one should sit in the hot sun or in the cold, in order to suffer. Therefore, the Torah states, "וכל מלאכה לא תעשו" – and you shall not do any work. מה מלאכה שב ואל תעשה אף ענוי שב ואל תעשה – Just as the mitzvah of not doing melacha, is a command to sit and not do, so too the mitzvah of afflicting yourself, is a command to sit and not do. That is, the mitzvah of affliction requires, not a direct inflicting of pain and discomfort, but a refraining from any activity that relieves such suffering.
The Gemara asks that perhaps the passuk is coming to command that in a case where one sits in the sun and becomes hot, we should not say to him, "Get up and sit in the shade.” Or where one sits in the shade and becomes cold, we should not say to him, “Get up and sit in the sun”? The Gemara answers מה מלאכה לא חלקת בה אף ענוי לא תחלוק בה - Just as you do not differentiate concerning when to apply the mitzvah of refraining from work, for it is a prohibition that applies in all situations, so too you should not differentiate concerning when to apply the mitzvah of affliction. Meaning, that in this case, if a person actively enters a sunny or shady area and sits there, he cannot fulfill this mitzvah of affliction, as this is a positive act and has already been excluded from the prohibition.
- The עינוי of the מן
The Gemara determines that the ענוי of Yom Kippur is derived from the עינוי of the mann and brings a machlokes Amoraim regarding the “affliction” caused by the mann. The Torah states: המאכלך מן במדבר...למען ענתך – Who feeds you mann in the midbar…in order to afflict you. Rebbe Ami and Rebbe Assi debate why eating mann was an affliction. One said: אינו דומה מי שיש לו פת בסלו למי שאין לו פת בסלו – One who has bread in his basket is not at all similar to one who does not have bread in his basket. Rashi explains that the one who no longer has bread left in his basket worries about tomorrow’s sustenance. The other one said: אינו דומה מי שרואה ואוכל למי שאינו רואה ואוכל – One who sees what he eats is not at all similar to one who cannot see what he eats. Rashi explains that when eating the mann one could experience the taste of any food he desired. But since they only saw the mann, they did not feel as satiated as one who could see the food .
