Issur Melacha and Issur Achila On Yom Kippur II

One more interesting he'arah on this topic.

Rav Shirkin in the Harirei Kedem (Siman 49) brings a Beis HaLevi (Chelek 1 Siman 18) that jsut like if one does melacha on Shabbos he is a mumar l'kol hatorah so too if one does melacha on Yom Kippur he is a mumar l'kol hatorah. (The rayah is from the Rambam Hil Geirushin 3:19 that if one who writes a get on Shabbos or Yom Kippur the get is batul and the kesef mishna explains because he is like an akum). Rav Shirkin then writes that Rav Moshe Soloveitchik added that since the issur achila and issur melacha of Yom Kippur comes from the same kedushas hayom, then just like if one does melacha on Yom Kippur he is a mumar l'kol hatorah, so too if one eats on Yom Kippur he is also a mumar l'kol hatorah.

Rav Shirkin asks on this Beis HaLevi, why is this whole idea true. B'shlama by one who does melacha on Shabbos, we can understand why you are a mumar l'kol hatorah because as the Rambam writes in Hil Shabbos (30:15) Shabbos is an os that HKBH created the world. However, what kind of os is represented by Yom Kippur? He leaves it as a tzarich iyun.

The Mesoras HaRav Machzor actually brings down this exact question on the Beis HaLevi and gives the following answer. The Rav compares Yom Kippur to Shabbas. Why is Yom Kippur called "shabbos shabboson". The Rav explained that whereas Shabbos represents the idea that HKBH created the world thru middas hadin, Yom Kippur represents the idea that the world is created thru middas hachesed. The medrash says that the "yom echad" in the possuk "vayehi erev vayehi boker yom echad" refers to Yom Kippur. Teshuva was created before the world and is a necessary component in sustaining the world. This is why keeping one who violates Yom Kippur is a mumar l'kol hatorah. Yom Kippur also represents a fundemental idea about HKBH and the creation of the world, just like Shabbos.