Why does the Torah insert the word "ve'Chol" (in "ve'Chol ha'Am Ro'im")?
Rashi: To teach us that there was not even one blind person among them. 1
What does the Torah mean when it writes that "all the people saw the Voices"?
Rashi (citing the Mechilta): It means that they literally saw what is otherwise impossible to see. 1
Hadar Zekenim: Hashem's voice is fire
Just as Hashem enables us to see physical objects and to hear sounds, He can just as well enable us to see what is normally heard and to hear what is normally seen, as R, Chanina ben Dosa stated in Ta'anis (25a) 'The One who tells oil to burn can just as well tell vinegar to burn!' (EC)
Which "Voices" did they see?
Ramban #2: Refer to 20:15:4:2
Rashbam: It refers to the stones and the hail that accompanied Matan Torah. 3
Refer to 20:15:2:3.
When did this take place?
Ramban #2: It took place before Matan Torah. 2 Petrified by the thunder, the flashes of lightning and the Shofar blasts 3 that they heard on the morning of Matan Torah, prior to the arrival of the Shechinah, 4 the people in the camp trembled with fear. 5 Meanwhile, Moshe soothed them and took them out to meet Hashem and they stood at the foot of the mountain. 6 At that point, the Shechinah descended in fire 7 and the mountain began to shake violently, 8 and the Shofar blast became louder and louder. 9 At that point, the terrified people moved backwards from the camp 10 and , asked Moshe that he should speak to them, and not Hashem - for fear that they would die. 11 Moshe reassured them that they had nothing to fear, but allowed them to remain where they were whilst he approached the thick cloud. 12
After the Aseres ha'Dibros, because they wee afraid either that Hashem would teach them all the Mitzvos directly (Rashbam), or that He had more to tell them now (Ibn Ezra). Refer also to question of 20:15:6:1.
See Ramban, who cites many proofs in support of this explanation.
Like it does when there is an earthquake and perhaps even more; as the Pasuk specifically writes in Tehilim (114:4).
The current Pasuk. They moved back twelve Mil (Targum Yonasan)
Because, following the vision, "their joints shuddered and their strength left them" (Daniel, 10:16).
What does the Torah mean when it writes "va'Yanu'u va'Ya'amdu me'Rachok"?
According to the voices that Yisrael saw were those of before Matan Torah, why does the Torah not tell us here about Yisrael's request after Matan Torah and Hashem's reply (See Devarim 5:20-27)?
Ramban: Because it wants to first spell out in detail the Mitzvos and Mishpatim, 1 which it taught briefly in the Aseres ha'Dibros
Rashi writes that they moved back 12 Mil. How could they leave the Techum? It was Shabbos!
Moshav Zekenim (2), citing R. Yehoshua: Since they were surrounded by the clouds, it is as if they were in one Chatzer.
Rashi explains according to the opinion that Techumim are mid'Rabanan. (PF)
Rashi, citing Shabbos 88b, learns from "Malchei Tzeva'os Yidodun Yidodun" (Tehilim 68:13) that angels helped Yisrael to return. The verse says Malchei (kings), not Mal'achei (angels)!
Moshav Zekenim citing Ri ha'Bechor, citing a Midrash: They were the highest angels, i.e. Micha'el and Gavriel. They are called kings to show their dearness.
How many voices were there?
Hadar Zekenim: The prefix Hei teaches five, and "Kolos" is at least two; each Dibur divided into seven voices, and into each of the 70 languages. 1
Moshav Zekenim (17): There were 10 voices, each stronger than the previous one.
It seems that this is even when Hashem said each Dibur by itself. How were they able to understand the first two, amidst 490 voices? It seems that this was a miracle. (PF)
Rashi writes that "Kol ha'Am Ro'im" teaches that n one was blind. Above (19:11), he said that we learn this from "l'Einei Kol ha'Am"!
Sifsei Chachamim: Here it teaches that even after Matan Torah, their eyes were not weak. Even one who looks at the Kohanim's hands [when they Duchan], his eyes weaken due to the Shechinah, and [one would think] all the more so after they saw a great Giluy Shechinah!