What are the connotations of "Yevarech'cha Hashem Veyishm'recha"?
Rashi #2 (in his initial manuscript): 'Hashem will bless you with sons and with daughters' - since daughters require protection'.
Ramban (according to Kabalah): Hashem will bless you from above 3 and guard you - like Zachor and Shamor, respectively..
Ba'al ha'Turim: "It corresponds to Avraham Avinu. 4
Targum Yonasan: 'Hashem will bless all your business dealings and guard you against all kinds of demons'. 5
Sifri: 'He will bless you with the B'rachos written explicitly in the Torah 6 - as the Pasuk writes in Ki Savo Devarim, 28:3 "Baruch Atah ba'Ir u'Varuch Atah ba'Sadeh ..."; and He will adhere to the B'ris that He made with your fathers. 7
Seforno: Because 'If there is no flour there is no Torah' (Avos, 3:17). See also Ba'al ha'Turim.
Rashi: To safeguard the first B'rachah - something that a human benefactor is unable to guarantee.
See R. Chavel's footnotes.
"Yevarech'cha" corresponds to Avraham, "Ya'er" to Yitzchak and "Yisa" to Ya'akov. See Ba'al ha'Turim here and on Pasuk 25 & 26.
See Peirush Yonasan.
See Torah Temimah, note 144 and Oznayim la'Torah in Pasuk 26 DH 'Veyasem l'cha Shalom'.
Sifri (ibid.); See Eikev Devarim, 7:12. See also Torah Temimah, who discusses a number of D'rashos that the Chachamim made on the current Pasuk.
Seeing as the Kohanim are blessing the community, why are the B'rachos said in the singular?
Ha'amek Davar: Because although the B'rachah is communal, each person receives the B'rachah according to his desert.