Guarding the Name reveals His holiness

בפסוק ולא תחללו כו' ונקדשתי.

On the verse, "And you shall not profane [My holy Name]… and I shall be sanctified [among Bnei Yisrael]" (Vayikra 22:32).

The Sefas Emes takes up the twin commands of the pasuk: the prohibition of chillul Hashem (profaning the Name) and the mitzvah of kiddush Hashem (sanctifying it).

כי ק"ה היא מצוה גדולה וזוכין לה ע"י שנשמרים בעצמם מאוד מחילול ה' ח"ו שאין לזה שיעור כדאי' בגמ' עד היכן ח"ה ע"ש ביומא.

For kiddush Hashem is a great mitzvah, and one merits it by guarding oneself very carefully from chillul Hashem, God forbid — which has no fixed measure, as it is stated in the Gemara, "to what extent is chillul Hashem [a concern]?" — see there in Yoma.

Sanctifying Hashem's Name is attained specifically through scrupulously avoiding any desecration of it. The Gemara in Yoma shows that the standard for what counts as chillul Hashem is boundless — the more refined a person, the more is demanded of him.

וכפי מה שנשמרים מזה זוכין לק"ה.

And in accordance with how much one guards against this, one merits kiddush Hashem.

The two are directly proportional: the more carefully one avoids chillul Hashem, the greater the kiddush Hashem one is granted.

וחכמים הגידו המחלל ש"ש בסתר נפרעין ממנו בגלוי.

And the Chachamim taught: one who profanes the Name of Heaven in secret, they exact punishment from him in public.

Chazal teach a principle of correspondence: a hidden desecration is repaid with a public exposure — what was done in concealment is brought to light.

א"כ מדה טובה מרובה השומר עצמו מח"ה זוכה שיתגלה ע"י כבוד שמים בעולם.

If so, [since] the measure of good is greater, one who guards himself from chillul Hashem merits that through him the glory of Heaven becomes revealed in the world.

Since reward outweighs punishment, the inverse must be even more true: one who quietly guards against desecration merits that, through him, kvod Shomayim is publicly revealed. Hidden faithfulness earns open sanctification.

כי ונקדשתי הוא הבטחה ג"כ בפרט ובכלל שבסוף יתגלה קדושת שמו ית' ע"י בנ"י.

For "and I shall be sanctified" is also a promise — both individually and collectively — that in the end the holiness of His Name will be revealed through Bnei Yisrael.

"V'nikdashti" is not only a command but a guarantee: ultimately, both for each person and for the nation as a whole, Hashem's holiness will shine forth in the world through Bnei Yisrael.

ובעוה"ז כתי' ולא תחללו ולעתיד יתקיים ונקדשתי.

And in this world it is written "you shall not profane," while in the future "and I shall be sanctified" will be fulfilled.

The present task in olam hazeh is the negative guarding against chillul Hashem; the full positive sanctification of the Name awaits the future redemption.

ומ"מ יש מעין זה גם בעוה"ז בימי המעשה ולא תחללו ועי"ז יתקיים בש"ק ונקדשתי.

And nonetheless there is something of this even in this world: on the weekdays, "you shall not profane," and through this, on Shabbos Kodesh, "and I shall be sanctified" is fulfilled.

A weekly taste of the future pattern exists already: the weekdays are the time of guarding against chillul Hashem, and that restraint flowers into the revealed kedushah of Shabbos, a foretaste of the ultimate v'nikdashti.

כמ"ש על שבת לדעת כ"א ה' מקדישכם.

As it is written concerning Shabbos, "to know that I am Hashem who sanctifies you" (Shemos 31:13).

Shabbos is the day when Hashem's sanctification of Bnei Yisrael becomes knowable and felt — the realization of "I am Hashem who sanctifies you."

ובתוך בנ"י כי בשבת מתאספין נשמות בנ"י ומתאחדין ברזא דאחד.

"Among Bnei Yisrael" — for on Shabbos the souls of Bnei Yisrael gather together and become unified in the mystery of Oneness (raza d'echad).

The pasuk's phrase "among Bnei Yisrael" is fulfilled on Shabbos, when the neshamos of Israel are drawn together and joined in the secret of Hashem's Oneness — sanctification happens through their unity.

וכמאמרם מסור עצמך וקדש שמי.

And as they said, "Give yourself over and sanctify My Name."

The deepest kiddush Hashem involves mesirus nefesh — giving oneself over entirely to sanctify Hashem's Name.

וביטול כל המלאכות לשבות בש"ק הוא מעין מסירת נפש:

And the cessation of all melachos, to rest on Shabbos Kodesh, is a semblance of mesirus nefesh.

Refraining from all creative work on Shabbos — surrendering one's own activity and will — is itself a small form of self-sacrifice, a weekly enactment of "give yourself over and sanctify My Name."

Summary: Kiddush Hashem is attained precisely by carefully guarding against chillul Hashem, whose standard is boundless. Since reward exceeds punishment, one who quietly avoids desecration merits that Hashem's glory be openly revealed through him. The full v'nikdashti is a promise for the future, but a weekly foretaste exists already: the weekdays' restraint ("do not profane") blossoms into the revealed kedushah of Shabbos, when the souls of Bnei Yisrael unite in Hashem's Oneness — and the cessation of all melachah is itself a form of mesirus nefesh that sanctifies His Name.