Why does it say "Beruchim Atem la'Shem"?
Malbim: In addition to the Brachah via Hashem's recall of us, you are already blessed via the encompassing Brachah from the beginning (creation).
Why is Hashem called "Oseh Shamayim va'Aretz"?
Radak: He made the upper and lower beings; He has the ability to bless whom He wants to.
Malbim: This teaches unlike the Goyim who think that Shamayim and Eretz are already made, and Hashem does not act on them, rather, the Ma'arachah conducts the world and acts in the land. Rather, Hashem constantly makes Shamayim and Eretz and renews the creation. He makes Shamayim influence conduct below, and He puts special Hashgachah in the land according to merits and deeds.
