Matan Torah revealing the hidden light and nullifying the yetzer hara

איתא במדרשות כי בעצרת אית בי' ביטול יצה"ר הענין הוא דאיתא יבוא טוב ויקבל טוב מטוב לטובים שתורה נק' טוב דכ' לקח טוב.

It is brought in the Midrashim that on Atzeres (Shavuos) there is the nullification of the yetzer hara. The matter is as it is taught: "Let the good one come and receive the good, from the Good One, for the good ones" — for the Torah is called "good," as it is written, "a good acquisition (lekach tov)."

Shavuos has the power to nullify the yetzer hara. This is hinted in the teaching that the "good" (Moshe) comes to receive the "good" (Torah) from the "Good" (Hashem) for the "good ones" (Bnei Yisrael) — the Torah itself being called "good," for it is a "good acquisition."

הענין הוא דכתיב וירא כו' את האור כי טוב ויבדל שגנזו שאין העולם כדאי להשתמש בו כו'.

The matter is as it is written: "And He saw... the light, that it was good, and He separated it" — that He hid it away, for the world is not worthy to make use of it, etc.

The primordial light of creation was so precious that Hashem concealed it (the ohr haganuz, the hidden light), since this world in its fallen state is not fit to benefit from it.

ומסתמא בשעת קבלת התורה נתגלה זה האור דכ' טוב ה' לכל ורחמיו על כל מעשיו.

And presumably, at the time of receiving the Torah, this light was revealed, as it is written, "Hashem is good to all, and His mercy is upon all His works."

At Matan Torah the hidden light shone forth once again, for at that moment Hashem's goodness and compassion were revealed to flow over all of creation.

פי' כמ"ש וירא אלקים כו' כל אשר עשה והנה טוב מאוד כו' ויברך כו'.

The meaning is as it is written: "And God saw all that He had made, and behold it was very good... and He blessed," etc.

This corresponds to the moment at the end of creation when Hashem looked over everything together and pronounced it "very good," granting it His blessing.

פי' שכשנעשה כל הבריאה אגודה אחת אז נתגלה וחל עלי' השגחת הבורא ית' לטוב.

The meaning is that when all of creation was made into a single bound bundle, then the hashgachah (providence) of the Creator was revealed and rested upon it for good.

When all the diverse parts of creation are unified into one whole, Hashem's loving providence becomes manifest and rests upon the world for the good.

ואז גם היצה"ר נתבטל.

And then even the yetzer hara is nullified.

In that state of unity and revealed providence, the yetzer hara loses its grip and is dissolved.

ודרשו חז"ל טוב מאוד על יצה"ר.

And Chazal expounded "very good" as referring to the yetzer hara.

The Sages taught that the word "very" in "very good" alludes to the yetzer hara, which is ultimately part of the good of creation when seen in its proper place.

ולכן כשנתגלה זה הטוב הגנוז אז ורחמיו על כל מעשיו.

Therefore, when this hidden good is revealed, then "His mercy is upon all His works."

Once the concealed goodness shines forth, even the yetzer hara is encompassed within Hashem's mercy, which extends over the whole of His creation.

וזה נתקיים במתן תורה שנתגלה פנימיות כל הבריאה.

And this was fulfilled at Matan Torah, when the penimiyus (inner essence) of all creation was revealed.

The Giving of the Torah accomplished exactly this — it laid bare the inner essence and hidden good within all of creation.

ז"ש וידבר אלקים כו' כל הדברים האלה לאמר.

This is the meaning of "And God spoke... all these words, saying."

The verse introducing the Aseres Hadibros hints at this revelation of the inner truth of everything.

פי' שהשי"ת גילה הנהגה שלו כי בעוה"ז נסתר זאת ויש כופרים בהבורא ית'.

The meaning is that Hashem revealed His way of conducting the world, for in this world this is hidden, and there are those who deny the Creator.

At Sinai, Hashem disclosed His governance of the world, which is normally concealed — a concealment so deep that some come to deny Him entirely.

אבל במתן תורה נתגלה הנהגת הבורא.

But at Matan Torah, the conduct of the Creator was revealed.

The Giving of the Torah removed the veil, making Hashem's hand in directing the world plainly evident.

ז"ש וידבר.

This is the meaning of "And He spoke (vayedaber)."

The term "speaking" itself signals this open revelation and proclamation of Hashem's presence.

ובזוה"ק לאכרזא מילין.

And in the Zohar: "to proclaim words."

The Zohar explains that the "speaking" at Sinai was a public proclamation, broadcasting the inner words of creation aloud.

כל הדברים פי' כל מה שנמצא בעולם וכל הדיבורים וכל צרופי אתוין שבמעשה בראשית.

"All the words" means everything that exists in the world, and all the utterances, and all the combinations of letters that are within the act of creation.

"All these words" encompasses the whole of existence — the ten utterances and the letter-combinations through which the world was created were all revealed at Matan Torah.

וכבר כתבתי מזה במ"א.

And I have already written of this elsewhere.

The Sefas Emes notes that he has discussed this theme in another place.

לכן נק' יום הביכורים שמתגלה בו כח הראשית והשורש שבכל דבר.

Therefore it is called Yom HaBikkurim (the Day of First Fruits), for on it the power of the "beginning" and the root within everything is revealed.

Shavuos is named the Day of First Fruits because it discloses the original creative force — the very "beginning" — and the inner root that lies within every created thing.

ולכן נקרא התורה ראשית שהיא ראשית ושורש כל הברואים:

And therefore the Torah is called "the beginning (reishis)," for it is the beginning and the root of all created beings.

The Torah is called "reishis" because it is the source and root from which all of creation flows — the inner essence revealed on Shavuos.

Summary: On Shavuos the yetzer hara is nullified, because Matan Torah revealed the hidden primordial light and the inner essence (penimiyus) of all creation. When the world is unified into one whole, Hashem's providence rests upon it for good and even the yetzer hara — the "very good" — is absorbed into His all-encompassing mercy. The Giving of the Torah laid bare Hashem's governance of the world and the creative letter-combinations behind all existence, which is why Shavuos is the Day of First Fruits and the Torah itself is called "reishis," the root of all created beings.