Aharon's bittul versus Korach's grasping

במדרש הנועדים על ה' בא וראה חסידותו של אהרן כו'.

In the Midrash on "those who gather against Hashem" (Bamidbar 16:11): come and see the chassidus (piety) of Aharon, etc.

The Sefas Emes opens with the Midrash that, against the backdrop of Korach's assembly "against Hashem," directs us to contemplate the piety of Aharon.

וכבר כתבתי לעיל מזה רק באתי להוסיף דאיתא בזוהר איזהו חסיד המתחסד עם קונו דעביד לי' קן כו'.

And I have already written above concerning this; I have come only to add that it is brought in the Zohar: who is a chassid? One who acts with chesed toward his Maker, who makes for Him a "nest," etc.

The Sefas Emes adds the Zohar's definition of a chassid: one whose devotion toward Hashem is so complete that he becomes, as it were, a "nest" — a dwelling place — for the Shechinah.

וכמ"ש תומיך ואוריך לאיש חסידיך כו' האומר לאביו ואמו כו' פי' ע"י הביטול זכה שישרה עליו השכינה ויהי' מדור וקן.

And as it is written: "Your Tumim and Your Urim to Your chassid (man of devotion)... who said of his father and mother [I have not seen them]," etc. (Devarim 33:8-9). The meaning is that through bittul (self-nullification) he merited that the Shechinah should rest upon him, and that he became a dwelling and a nest.

The verse blessing Levi as the "chassid" who disregarded even his own parents for Hashem's sake shows that through total bittul of self, a person merits to have the Shechinah rest upon him, becoming a dwelling place for the Divine Presence.

א"כ נועדים על ה' ממש כביכול.

If so, they are "gathered upon Hashem" in a literal sense, as it were.

By a holy reading of the same phrase, the truly devoted become a place where Hashem "rests upon them" — the very opposite of Korach's rebellious gathering "against Hashem."

והוא היפוך מדת קרח ויקח כו'.

And this is the opposite of the trait of Korach, "and Korach took," etc. (Bamidbar 16:1).

Korach's defining trait was "taking" — grasping for himself — which is the polar opposite of Aharon's self-nullification and giving.

ואהרן מה הוא.

"And Aharon, what is he?" (Bamidbar 16:11).

Aharon's response embodies bittul — "what am I?" — humbly regarding himself as nothing, the very inverse of Korach's self-assertion.

ועל הפרש זה כתיב מדרכיו ישבע סוג לב ומעליו איש טוב מהארה היורדת עליו כמ"ש במ"א בפ' עושה שלום במרומיו יעשה שלום עלינו ע"ש:

And concerning this distinction it is written: "the one whose heart turns away will be sated from his own ways, and a good man from what is above him" (Mishlei 14:14) — from the illumination that descends upon him, as I have written elsewhere on "He who makes peace in His heights, may He make peace upon us," see there.

The verse contrasts two types: the "turned-away heart" (Korach) is filled only from his own ways — his self-centered grasping — while the "good man" (Aharon) is sustained "from above," by the divine illumination that descends upon him because he has made himself a vessel through bittul. This parallels the prayer that Hashem, who makes peace among the heavenly forces, should make peace upon us.

Summary: Against Korach's assembly "against Hashem," the Sefas Emes highlights Aharon's chassidus: the true chassid, through complete bittul of self, makes himself into a "nest" and dwelling for the Shechinah, so that Hashem rests upon him. This is the exact opposite of Korach, whose trait was "taking" and self-assertion — the "turned-away heart" sated only from his own ways, as opposed to the "good man" who is sustained by the illumination that descends from above.