True achdus needs righteous leadership

ובגמ' ובמד' בקהלם אל תחד כבודי בעדת קרח פי' דכתיב ויקהלו על משה ועל אהרן.

And in the Gemara and Midrash on "in their assembly let my honor not be united" — this refers to the congregation of Korach, as it is written, "and they assembled against Moshe and against Aharon."

Yaakov's words "let my honor not be joined to their assembly" were read by Chazal as a prophetic distancing of himself from Korach's gathering against Moshe and Aharon.

אבל לא הי' כניסי' לשם שמים ולא נתקיים כי כח האסיפה לבוא לאחדות ולעורר השורש של יעקב אבינו כחן של בנ"י.

But it was not a gathering for the sake of Shomayim, and so it did not endure — for the power of assembly is to arrive at achdus and to awaken the root of Yaakov Avinu, the strength of Bnei Yisrael.

A true gathering must be l'shem Shomayim; its whole purpose is to reach unity and draw on the root-power of Yaakov. Korach's assembly lacked this, so it could not last.

וזהו סופה להתקיים פי' לעורר הסוף והתכלית אחדות הגמור.

And this is the meaning of "its end is to endure" — to awaken the ultimate end and purpose, complete achdus.

The Mishnah's phrase that a gathering "for the sake of Heaven will endure" means it reaches toward the final goal of total unity.

אבל בקהלם אל תחד ולא באו להאחדות.

But "in their assembly let it not be united" — for they did not arrive at achdus.

Korach's crowd never reached real unity, so Yaakov's honor would not be associated with it.

וזהו שאמרו כל העדה כו' קדושים כו'.

And this is what they said: "the entire congregation… are all holy etc."

Korach claimed the whole assembly was already holy and united, needing no leaders.

אמת הי' שבכח התאספות בנ"י מעוררין הקדושה והאחדות והשראת השכינה כמ"ש ויהי בישורון מלך בהתאסף.

It was true that through the power of Bnei Yisrael gathering together, they awaken kedushah and achdus and the resting of the Shechinah, as it is written, "and He became King in Yeshurun when [the heads of the people] gathered."

Korach's premise was not wholly false: collective assembly really does arouse holiness, unity, and the Shechinah's presence — but only when done properly.

אבל צריכין סיוע שיוכלו להתאסף ולהתאחד.

But they require assistance in order to be able to gather and to unite.

Genuine unity does not come on its own; the people need a channel of help to truly come together.

וזה הי' בכח מרע"ה ועבודת הכה"ג.

And this came through the power of Moshe Rabbeinu and the avodah of the Kohen Gadol.

That necessary assistance flows specifically through Moshe Rabbeinu and the service of Aharon — the very leaders Korach sought to discard.

לכן כשרצו להתאסף חוץ מכחם לא הועילו כלום:

Therefore, when they sought to gather outside of their power, they accomplished nothing.

By attempting to unite while rejecting Moshe and Aharon, Korach's group cut themselves off from the only source that makes unity real — so their assembly came to nothing.

Summary: The power of a gathering is to reach true achdus and awaken the root-strength of Yaakov, but only when it is l'shem Shomayim. Korach's claim that "the whole congregation is holy" rested on a real truth — collective assembly does arouse kedushah and the Shechinah — yet such unity requires the enabling power of Moshe Rabbeinu and the avodah of the Kohen Gadol. Because Korach tried to unite while rejecting those leaders, his assembly had no endurance and achieved nothing.