What is the difference between "Hashem" and "Elokim"?
What are the implications of "Hashem Elokeinu"?
Seforno: It implies that Hashem is the One whom we choose from all the deities, since He is the only One who is able to provide us with all our needs. And due to His superior strength, it is to Him alone that we will bow down; and because it is to Him alone - directly, without any medium - that we look to for all our needs, that we will Daven to Him alone.
What is then the exact meaning of "Hashem Elokeinu Hashem Echad"? Why does the Pasuk insert the Name "Hashem" twice?
Ramban: It is because Hashem performed with Moshe wondrous deeds in order to elevate him in order to enhance his name. 1
Targum Yonasan: Because it is referring to a dialogue between Ya'akov and his sons, where, in reply to his query as to whether their Emunah was complete, they exclaimed in unison 'Sh'ma Yisrael Avinu, Hashem Elokeinu ... !' 2
Therefore he found it necessary to include himself on this instance. Presumably, it is for the same reason that he used the same Lashon in Devarim, 1:6 - since he was referring to Har Sinai, where many of those wondrous deeds occurred.
Targum Yonasan: To which Ya'akov responded 'Baruch Shem K'vod Malchusdo ... !'.
What is the meaning of "Hashem Echad"?
Seforno: It means that there is nothing that can compare to the existence of Hashem, who created existence when there was nothingness. Consequently, He is detached from this (perishable) world, from the world of the planets, from the world of angels, and He exists Alone in the fourth world. 3
Rashbam: We will serve Hashem, who alone is our G-d. 4 And under no circumstances will we combine any other deity with Him, even to divine, whilst still believing that there is no G-d other than Hashem. 5
What is the difference between the Mitzvah of "Anochi" (in the Aseres ha'Dibros) and that of "Sh'ma Yisrael"?
Ramban #1: "Sh'ma" is coming to elaborate on the Mitzvah of "Anochi", which is the unification of Hashem's holy Name.
Ramban #2 (in Yisro) 1 : "Anochi is the Mitzvah of Kabalas Ol Malchus Shamayim, whereas "Sh'ma" is that of the unification of Hashem's holy Name.
Why is the 'Ayin' in "Sh'ma" large?
Seforno: To hint that we should open our eyes and think deeply about thr Oneness of Hashem. 1
Ba'al ha'Turim #1: Because Hashem gave the Torah which has seventy names and can be explained in seventy ways to Yisrael, who have seventy names. 2
Ba'al ha'Turim #2: Refer to 6:4:7:4.
And why is the 'Daled' in "Echad" written large?
Ramban (according to Kabalah): It hints at the great Name of Hashem. 1
Seforno: Because Hashem exists alone in the fourth world. 2
Ba'al ha'Turim #1: To teach us that we should declare Hashem King over Heaven and earth and over all four directions.
Ba'al ha'Turim #2 (citing Midrash): To avoid confusing it with a 'Reish' (Chas ve'Shalom). 3
Ba'al ha'Turim #3: In conjunction with the large 'Ayin' in Echad, it spells 'Eid' - a hint that Yisrael testify on Hashem's Oneness. 4
Ramban: See Yeshayah, 63:12. Corresponding to which the Chachamim inserted the Pasuk "Baruch Sheim ... " in the Sh'ma - See Pesachim, 56a (Ramban).
Ibid: And by the same token the 'Reish' in "Lo Sishtachaveh le'Eil Acher" (Shmos 34:14) is written large to avoid confusing it with a 'Daled' (Chas ve'Shalom).