Having said above "Ve'ahavta es Hashem Elokecha", why does the Torah see fit to add "Es Hashem Elokecha Tira"?
Ramban #1: To deter a person from sinning and getting punished.
Ramban #2: Refer to 6:5:3:2*.
Ramban #3 (citing Temurah, 3b): It is a warning against uttering the Name of Hashem in vain.
What do we learn from the word "Es Hashem Elokecha Tira"?
What are the connotations of "Oso Sa'avod"?
Ramban #1: It means that one is obligated to serve Hashem like an Eved serves his master.
Ramban #3 (citing the Ibn Ezra): "Es Hashem Elokecha Tiyra" implies not to contravene Mitzvos Lo Sa'aseh, and "Oso Sa'avod", to keeping the Mitzvos Asei. 3
Ramban (citing the Sifri) and Rashi, commenting on the Pasuk in 13:5 "ve'Oso Sa'avodu" - 'in the Beis-Hamikdash' (Ramban: incorporating Korbanos, singing and bowing, which all fall under the category of Avodah - as the Torah indicates in Bamidbar 18:7, 23').
Ramban, citing the same Sifri.
See Ramban's objection to this explanation.
Since when is it a Mitzvah to swear by Hashem's Name?
Ramban #1: The Pasuk means that one may only swear by the Name of Hashem, but not by the Name of any other god. 4
Ramban #2 (citing Temurah, 3b), Rosh and Targum Yonasan: The Pasuk is coming to permit swearing by Hashem's Name truthfully. 5
Ramban #4: Your Yir'as Shamayim will be so deep and you will be dedicated to His service 6 to such an extent, that you will always swear by His Name - even if it is to do something unpleasant - and abide by your oath.
Even though the two preceding statements in the Pasuk are Mitzvos - as the Ramban explains.
Ramban and Rosh: Like Avraham, Yosef and Iyov, who are called 'Yir'ei Elokim'.
Ramban: Someone whose only Avodah is that of Torah and Mitzvos.
Even if it is not for a Mitzvah - See Ramban.
Ramban: To the point that every mundane act that you perform is to serve Hashem - See Ramban DH 'O Yomar'.
Why does the Pasuk insert "u'Bo Sidbak" in Eikev (Devarim 10:20) and omit it here?
Why does the Torah add "u'Bo Sidbak" below (in 10:20) and omit it here?
Ba'al ha'Turim: There, the Torah mentioned earlier Hashem's love for the Avos, which obligates their descendants to cling to Him.
Panim Yafos #1: Here it discusses swearing to fulfill Mitzvos; one need not cling to Hashem for this. Below it discusses Shevu'as ha'Reshus, e.g. to avoid paying in Beis Din. That is only for one who also cling to Hashem.
Panim Yafos #2: Here it discusses Dor ha'Midbar. All of them were Chachamim (they learned from Moshe all the time), and clung to Hashem