The Midrash says1 that the Jewish people slept the entire night before Mattan Torah, the giving of the Torah. They did so, because the “sleep of Shavuos is sweet and the night is short.” Moreover, the Midrash goes on to state: “on that night, even fleas did not bite them.”

The Midrash concludes that when G‑d came at dawn and found the people asleep, it was necessary to rouse them. This is the meaning of G‑d’s query:2 “Why did I arrive and no one was there? I called, and nobody answered.”

Our Sages inform us3 that when the Jewish people heard that, 50 days after their departure from Egypt, they would receive the Torah, they became filled with an intense desire to acquire it. They therefore began counting the days that remained until the Torah would be given.

Bearing in mind that, seven weeks prior to Mattan Torah, the Jews were already extremely impatient to receive it, we can imagine how much greater was their yearning on the night before it was given. This being so, how was it even possible for them to sleep, let alone sleep so soundly?

This leads us to the conclusion that their going to sleep on that night was not, G‑d forbid, because they ceased thinking about the Torah, but quite the contrary, that going to sleep that night served to prepare them in some way to receive it.

Additional proof that this was indeed so can be adduced from the fact that the fleas did not bite them that night. If going to sleep constituted a lack of interest in receiving the Torah, G‑d would not have kept the fleas from biting.

How was their going to sleep a preparation for receiving the Torah?

The Alter Rebbe writes4 that no matter how great a soul’s comprehension of and union with G‑dliness while clothed in a body, it can in no way compare to the soul’s cleaving to G‑d prior to its descent, when it was unencumbered by a physical body. For the body is simply incapable of experiencing such holiness.

When a person sleeps, the major portion of his soul leaves his body and ascends above.5 The soul of a sleeper can therefore attain much greater levels of spiritual comprehension.

This is why the Jews went to sleep just prior to Mattan Torah : They wanted their souls to attain greater spiritual heights. The Jewish people thought that this intense spiritual elevation would be the best possible preparation for the tremendous revelation they would soon be receiving from above.

Their good intentions notwithstanding, G‑d was displeased with their going to sleep, for they should have prepared for Mattan Torah in another manner:

The unique accomplishment of Mattan Torah — as opposed to mitzvos performed before the Torah was given — was that the mitzvos a Jew performed afterwards refined and elevated the objects with which they were performed; the objects themselves became holy. It is specifically by working with the physical and refining one’s physical body and surroundings that one attains union with G‑d’s Essence,6 something that cannot be accomplished by the soul alone.

Since Mattan Torah served to enhance the spiritual service of a soul within a body, it follows that the preparation for receiving the Torah should have been in a like manner; not a flight from the body, but rather an effort within the framework of a corporeal soul.

Based on Likkutei Sichos, Vol. IV, pp. 1024-1027