What are the connotations of "Im Lo Sishm'u"?
Rashi: It means 'If you do not listen to study Torah diligently'. 1
Seforno: It means 'If you don't adhere to My statutes'. 2
Targum Onkelos: It means 'If you do not accept My commands.
Targum Yonasan: It means 'If you are not willing to listen to the teachings of the Chachamim who teach My Torah'.
What are the implications of the word "Li"?
Rashi: This implies someone who knows his Master and intentionally rebels against Him. 1
What is the significance of the sequence "Im Lo Sishm'u Li" and "v'Lo Sa'asu ... "?
Rashi: If you don't learn, you won't (you can't) keep the Mitzvos.
Seforno: If you don't adhere to Hashem's statutes, you won't keep the Mitzvos.
Targum Onkelos: If you do not accept My commands and do not keep My Mitzvos.
Targum Yonasan: 'If you are not willing to listen to the teachings of the Chachamim who teach My Torah and you willingly decline to keep My Mitzvos'.
What is the difference between the current set of Berachos and the Berachos in Shemos (23:25, 26)?
Ramban (11): The Berachos in Shemos are hidden miracles, 1 which occur on occasions, sometimes to the people as a whole, sometimes to individual who serves Hashem; 2 whereas the miracles - albeit hidden miracles too - listed here, are public miracles that affect the entire nation 3 - on an ongoing basis, which will materialize when Yisrael are all Tzadikim. 4 This is situation that is entirely supernatural, and is a clear indication that Hashem is with us. 5
Ramban: Of which the Torah is full.
Ramban: Indeed, sometimes even Resha'im experience them.
Ramban: Which explains why the Torah keeps on repeating the word "ha"Aretz" in its various forms. And it is by the same token that the Kelalos that follow, are ongoing and affect the entire nation - See verse 19, Devarim 29:19, 21, 23, 24, 59. (See Ramban from DH 'v'ha'Chlal' till the end of the Pasuk, who elaborates).
Ramban: And that an entire nation should experience, permanently, a regular timely rainfall, bountiful crops, tranquility, peace, good health, might and defeated enemies is something unique, that the world has never seen.