To which era do the current B'rachos pertain?
Seforno: Up to and including Pasuk 8 pertains to the era of the first Beis-Hamikdash, whereas from Pasuk 9 pertains to that of the second Beis-Hamikdash - predominantly to the miracles that Shimon ha'Tzadik 1 experienced during his lifetime.
Refer also to 28:69:2:1.
Why does the Torah use the double expression "Im Shamo'a Tishma"?
Refer to 15:5:1:1-3.
Ba'al ha'Turim: "Shamo'a Tishma" has the same Gematriya as 'le'Divrei Torah u'le'Divrei Chachamim. 1
Sukah, 46b #1: To teach us that the Midah of Hashem is not like that of a human-being. The Midah of a human-being can take in when it is empty, but not when it is full, but that of Hakadosh-Baruch-Hu only takes in when it is full - 'If you will listen, you will hear again, but if you don't, you won't!' - in keeping with the principle 'Mitzvah Goreres Mitzvah!'
Sukah, 46b #2: If you listened to the old (to revise what you have learned), you will listen to the knew (you will be able to learn new things. 2
What are the connotations of the words "Lishmor La'asos"?
Rosh: It means that we should learn in order to put into practice.
Oznayim la'Torah: "Lishmor" refers to the - Mitzvos Lo Sa'aseh; "La'asos" to the Mitzvios Asei.