What did "Vehigbalta es ha'Har" entail?
Rashi and Rashbam: Moshe had to actually place markers along the borders of Har Sinai and to warn Yisrael not to cross them.
What are the connotations of "Leimor"?
Rashi: It means that the markers would 'tell them' not to go past them. 1
Otherwise, it would have been more appropriate to write "ve'Amarta aleihem". See also Sifsei Chachamim.
Why were the people forbidden to ascend the Mountain?
Oznayim la'Torah: Because Moshe was having a private audience with Hashem, nobody was allowed to be present, 1 (even though they were permitted to listen).
Oznayim la'Torah: It is similar to the Kohen Gadol on Yom Kipur, about which the Torah writes in Acharei-Mos, Vayikra, 16:17 "ve'Chol Adam Lo Yih'yeh be'Ohel Mo'ed .... See Oznayim la'Torah who elaborates.
Why was a seemingly- minor infraction (passing the boundary) punishable by death?
Seforno: To serve as a deterrent - to prevent the people, who were already keen to come closer, from breaking through and seeing more, in which case many of them would die and Hashem's Simchah would be disturbed, when their corpses rendered the location impure and when their relatives would mourn their death, with the result that the Shechinah would not rest with them.
How would someone who transgresses die?
Moshav Zekenim: He will be stoned bi'Yedei Shamayim, even though the Shechinah is there, like Nadav and Avihu died in the Mishkan. 1
Rashbam: The People will kill him (refer to 19:13:1:1).
Targum Yonasan: Refer to 19:13:1:2.
Not bi'Yedei Adam, since Hashem said - in Pasuk 13 - "Lo Siga Bo Yad!".
