Zerizus guards the love of Torah and mitzvos

במד' צו את אהרן הה"ד על כל פשעים תכסה אהבה כו'.

In the Midrash on "Command Aharon" (Vayikra 6:2): this is what is written, "over all transgressions love covers" (Mishlei 10:12).

The Midrash links the command to Aharon with the verse that love "covers" all sins, which the Sefas Emes will explain as the love of Torah.

זה אהבת התורה כדכתיב מים רבים לא יוכלו לכבות כו'.

This is the love of Torah, as it is written, "many waters cannot extinguish [the love]" (Shir HaShirim 8:7).

The "love that covers all transgressions" is the love of Torah, a flame so powerful that no flood of opposition can put it out.

ולכן אין עבירה מכבה תורה.

And therefore a sin does not extinguish Torah.

Because the love of Torah is unquenchable, even sin cannot extinguish the Torah within a person — its light endures despite his failings.

וזהו בחי' אהבה רבה.

And this is the aspect of "ahavah rabbah" (great love).

The love of Torah corresponds to the blessing of "ahavah rabbah" — Hashem's great, boundless love that no sin can quench.

ואהבת עולם הוא בחי' המצות.

And "ahavas olam" (everlasting love) is the aspect of the mitzvos.

The parallel blessing of "ahavas olam" corresponds to the mitzvos — the love expressed through concrete deeds, which require constant guarding.

וצריכין בכל יום לעורר את האהבה וזה הי' כוונת הקרבנות כמ"ש זאת התורה לעולה כו' ולחטאת כו' הכל לעורר בחי' האהבה שהיא התורה ולכן לא לן אדם בירושלים ובידו עון שהתמידין מכפרין.

And one must awaken the love every day, and this was the purpose of the korbanos, as it is written, "this is the Torah of the olah... and of the chatas..." (Vayikra 7:37) — all to awaken the aspect of love, which is the Torah; and therefore no person would lodge overnight in Yerushalayim with sin in his hand, for the daily tamid offerings would atone.

The love of Torah must be rekindled daily, which was the inner aim of the korbanos. The verse calls all the offerings "the Torah of..." because they served to reawaken the love that is Torah; this is why the constant tamid offerings atoned so that no one remained in Yerushalayim overnight bearing sin.

אבל לעורר את האהבה הוא ע"י המצות כמ"ש צו את אהרן והמצות בעשי' דעבירה מכבה מצוה ולכן צריך שמירה ביותר כמ"ש חז"ל ושמרתם את המצות כשם שאין מחמיצין המצה כך המצוה אם בא לידך עשה מיד.

But awakening the love is through the mitzvos, as it says "Command Aharon"; and the mitzvos are in the realm of action, where "a sin does extinguish a mitzvah," and therefore they require greater guarding, as Chazal said: "and you shall guard the matzos" — just as one does not let the matzah become chametz, so too with a mitzvah, if it comes to your hand, do it immediately.

While Torah itself cannot be extinguished by sin, a particular mitzvah can be lost through sin, so mitzvos demand extra vigilance. Chazal read "ushmartem es ha'matzos" (guard the matzos) as "ha'mitzvos" (the mitzvos): just as matzah must not be allowed to rise into chametz, a mitzvah must be seized and done at once, without delay.

ושמירה להמצות הוא בכח הזריזות.

And the guarding of the mitzvos is through the power of zerizus (alacrity).

The way to protect a mitzvah from being lost is zerizus — performing it with eager promptness before any delay can spoil it.

וזריזות מצפרא כמ"ש וישכם כו' בבוקר.

And zerizus is from the early morning, as it is written, "and he rose early... in the morning" (Bereishis 22:3).

True alacrity begins at the start of the day, like Avraham who "rose early in the morning" to fulfill Hashem's command without hesitation.

פי' להיות הראשית בכל יום עבודת הבורא.

Meaning: that the beginning of each day should be the service of the Creator.

Zerizus "from the morning" means dedicating the very first part of every day to avodas Hashem, setting its tone from the outset.

זה מיד ולדורות שע"י שעושין המצוה בזריזות נשאר מזה דבר של קיימא.

This is "immediately, and for the generations" — for through performing the mitzvah with zerizus, something enduring remains from it.

A mitzvah done with alacrity is not only acted upon "immediately" but leaves a lasting, permanent imprint "for the generations" — its energy endures beyond the moment.

ואיתא אור לי"ד בודקין החמץ לאור הנר.

And it is taught: on the eve of the fourteenth [of Nissan] one searches for the chametz by the light of a candle.

The Sefas Emes brings the halachah of bedikas chametz, searching by candlelight, and reads it as a sign of the enduring light created by an earlier mitzvah of zerizus.

כי מצוה ראשונה שקיימו ישראל בי"ד בזריזות כמ"ש וילכו ויעשו כו'.

For the first mitzvah that Yisrael fulfilled on the fourteenth with zerizus, as it is written, "and they went and did" (Shemos 12:28).

The korban Pesach in Mitzrayim was the first mitzvah Bnei Yisrael performed with eager alacrity, as the verse stresses "they went and did" it without delay.

נשאר אור הנר בזה היום לדורות.

The light of the candle remained on this day for the generations.

That original zerizus generated an enduring "light" attached to this date, which is why we search for chametz by candlelight on this very day throughout the generations.

ובזה הכח יכולין לבדוק ולבער את החמץ:

And with this power one is able to search out and destroy the chametz.

It is precisely this lasting light of zerizus that empowers us to search out and eliminate the chametz — symbolic of removing the yetzer hara and spiritual corruption.

Summary: The "love that covers all transgressions" is the love of Torah — an unquenchable flame ("ahavah rabbah") that no sin can extinguish, while the mitzvos ("ahavas olam") operate in the realm of action where a sin can extinguish a mitzvah and therefore demand extra guarding. This love must be rekindled daily, as the korbanos did, and the way to protect a mitzvah is zerizus — doing it at once, from the very start of the day, like matzah that must not be allowed to sour. Such alacrity leaves an enduring light: the first mitzvah done with zerizus on the fourteenth of Nissan left a lasting "candle-light" by which, to this day, we search out and destroy the chametz.