What is the connection between this Pasuk and the previous Pesukim?
Rashi: 'You will only be considered wise in the eyes of the nations (when you study the words of the Torah) if you will not forget them and fulfill them correctly, but if you will make them crooked due to forgetfulness, they will consider you fools.
Ramban: Following the warning to keep all the Mitzvos, the Chukim and the Mishpatim, the Torah is now issuing a warning (a Mitzvas Lo Sa'aseh) never to forget Ma'amad Har Sinai, the source of all the Mitzvos, with everything that they saw and what they heard there - the thunder, the flashes of lightning, Hashem's Kavod and His Greatness, and how they heard His words coming from the fire. And then to pass all of this on to your children and grandchildren. 1
Ramban: And as the Pasuk goes on to explain, this is because the objective of Ma'amad Har Sinai was in order to learn to fear Hashem for all generations, until the end of time.
What are the implications of "Hishamer l'cha u'Shemor Nafsh'cha ... "?
Berachos, 32b: It is a warning against endangering one's life. 1
Shevu'os, 36a: It teaches us thar someone who curses imself, ytransgresses a Lo Sa'aseh 2 (or even two).
Why does the Torah see fit to issue a double warning and to add the word "Me'od"? Why is remembering Ma'amad Har Sinai so important?
Ramban: Before presenting the Aseres ha'Dibros, the Torah wants to impress upon us the fact that it is Hashem who gave us the Torah. Had we received it from Moshe Rabeinu - notwithstanding the fact that his Nevu'ah was supported through signs and wonders, if a subsequent Navi or dreamer would arise and issue commands that clash with the Torah (that we heard from Moshe), and verify his words with a sign or a wonder, it would create a doubt in our minds as to the veracity of Moshe's words. But now that we received the Torah from Hakadosh-Baruch-Hu Himself, without a medium - borne out by what we saw and heard at Har Sinai, 1 we will have no doubt that whoever tries to make any change in the Torah is an imposter.
Seforno: Because otherwise, you may forget the Torah that you were taught there.
What is the significance of the words "ve'li'Venei Vanecha"?
Kidushin, 30a #1: One is obligated to teach one's grandson Torah. 1
Kidushin, 30a #2: One who teaches his son Torah, it is considered that he taught him, his [son's] son, his [son's] grandson, until all generations.
Kidushin, 30a #3: One who teaches his grandson Torah, it is considered that he received it from Sinai 2 (which the next verse discusses).
What are the connotations of the word "Yom asher Amadta ... "?