The Yalkut Shimoni (Mishlei, 9, ois 944) teaches that when Moshiach comes, there are only two Yomim Tovim that we will continue to observe, while all the others will no longer be celebrated.
Only Yom Kippur and Purim will be observed once Moshiach comes.
The Megillah states, “And these days of Purim should never cease from among the Jews, nor shall their remembrance perish from their descendants” (9:28). Purim is mandated never to cease to exist. It will continue to be observed forever.
Regarding Yom Kippur, the Torah tells us, “This shall be to you an eternal decree to bring atonement upon Bnei Yisroel for all their sins once a year” (Vayikra 16:34). Yom Kippur is to be persevered for posterity, observed for all time.
The Shelah HaKadosh (Yoma, ois 142) wonders why these two specific Yomim Tovim will never be bateil? The Shelah advances a concept that is very similar to the idea we have presented from Rav Hutner.
He states that Purim and Yom Kippur are very similar in nature. They both work to counter the forces of evil, the instigators of sin. Purim destroys the forces of the Samach Mem, the influence of the angel of Eisav in this world, and Yom Kippur obliterates the Samach Mem himself, the Sotan. Both days serve to remove barriers to avodas Hashem. Using the terminology presented by Rav Itzele Peterburger, and Rav Yitzchak Hutner, we would use the phraseology that they work synergistically to remove the palga alai and the palga alayich to which Yitzchak referred.
The added insight gleaned from the Shelah HaKadosh is that both of these sources of sin, both of these instigators, are rooted in one source, the Samach Mem. The Samach Mem is essentially the same entity as Eisav, the yetzer horah, and the Sotan. The only difference is that Eisav exists in our physical world, while the yetzer horah and Sotan operate in the spiritual realm.
Since these are two days that serve to eradicate both incarnations of the Sotan, they will never be abolished. They will always be observed to assist with the destruction of the yetzer horah. Yom Kippur and Purim are thus intrinsically bound, as they are both intended to accomplish one unified task.
May we be zocheh to take full advantage of both of these sanctified days and successfully eradicate all hindrances to our avodas Hashem. Doing so will reveal our deepest, most inner desire, that it is our will to do His will: Retzoneinu laasos retzonecha. (Based on a much lengthier essay written by R’ Doniel Glatstein which can be found in his sefer, “The Concealed and the Revealed”, titled “Yom Kippur: A Day Like Purim”).
