On the third day, Hashem shall descend …on Har Sinai. You shall set boundaries for the people all around, saying, “Beware of ascending the mountain or touching its edge. Whoever touches the mountain will die. A hand shall not touch it…for he shall not live. Upon an extended sound of the shofar, they may ascend the mountain.
Meshech Chochmah: No sooner does the Torah impose the restriction against touching the mountain in our pesukim then the Torah tells us just when this restriction would be lifted. Which is strange, because this is not the way the Torah deals with the other restriction linked to the giving of the Torah. The people were also told that they were to separate from their wives beginning a few days before Matan Torah. This restriction as well would come to an end at some tine after the conclusion of the maamad ha-nivchar. The people are eventually told, “Return to your tents” – but this is recorded in the text only after the Ten Commandments and much more. Why is the Torah much quicker to write about the relaxing of the ban against touching the mountain?
A simple answer is that lifting the restriction against contact with the mountain is a matter of proper etiquette. The Torah used harsh language in conveying the ban; it spoke of the certainty of people dying. Derech eretz demands that a note like that should not be sustained. The Torah immediately changes its tone by speaking of the lifting of the restriction that carries such dire consequences.
In a sense, this begs the question. Why was a transgression of the touching ban treated so severely in the first place?
We begin our answer with a basic observation: A chief concern of the Torah is the eradication of any idolatrous thoughts or tendencies from our people. Part of our utter rejection of avodah zarah is the non-physicality of G-d. It was important to stress to the Bnei Yisrael that in their encounter with HKBH at Sinai, there was no physical element. Hashem was not “seen;” He did not take on any physical appearance or form. He did not because he can not! Form, appearance are related to substance, boundaries, dimensions – all elements that simply do not and cannot relate to His Being.
A corollary of the above is that the quality of holiness natively resides in only one Being – namely, Hashem Himself. There is nothing in the created world – nothing – that is inherently holy other than He. Hashem wished that impressed upon the Bnei Yisrael at the time of matan Torah. It was crucial that they not have any mental space in which to think that the Torah was given on a particular mountain because of some inherent kedushah that it possessed. The Torah therefore presented to the people a matched set of realities. On the one hand, the mountain was treated as holy. On the other, they were immediately informed that the holiness – a holiness that was strictly enforced – was temporary. As soon as the shofar sounded, they would be permitted to trample the mountain to their hearts’ content. Moreover, even their animals would be free to graze upon it, and otherwise treat it in an undignified manner, as animals do!
Clearly, if the mountain could be treated so shabbily afterwards, its holiness could not be regarded as inherent and essential. The people learned that its kedushah was not intrinsic, but extrinsic – it came about because of the Shechinah’s presence upon it. As soon as the Shechinah departed, the kedushah vanished.
This treatment carried over into the beis hamikdosh – a place with much more lasting kedushah! It was certainly important here to underscore that there was no intrinsic spiritual quality in the building. So we find that those who are tame’im – even those who are afflicted with tumas meis, the most severe form of tumah – may nonetheless touch the outside surface of the building. This reinforced the idea that the kedushah was a function of the luchos and the Shechinah that resided inside the building, and filled it with kedushah while they were there.
The take-away lesson is that kedushah of a lasting form is never a function of G-d’s actions – and it goes without saying that it is no magic, mystical property that is simply inherent in some physical item. Where kedushah is caused by Him, it is simply a consequence of His presence, and disappears as that presence is removed. The shofar sounded to inform the people that the Shechinah had left the mountain. It’s kedushah immediately vanished, and it became no more holy than any rock pile. Longer lasting kedushah is created only by the actions of human beings, such as the kedushah of the beis hamikdosh.
It therefore becomes necessary to retool our understanding of a later pasuk. It is usually translated as, “Moshe said to Hashem: ‘The people cannot ascend Har Sinai, for You have warned us, saying, “Cordon off the mountain and sanctify it.”’ We understand, however, that Moshe did nothing to make the mountain holy. Its holiness was entirely a function of the presence of the Shechinah. Rather, the pasuk must be understood as referring to Hashem. “You have warned us to cordon off the mountain so that You will come and descend upon it.” That will create a temporary holiness on Har Sinai, one that will depart whenever the Shechinah decides to leave.
 Based on Meshech Chochmah, Shemos 19:13
 Shemos 19:14
 Devarim 5:27
 Shemos 19:23