What does the Gemara mean? What kindness did Hashem do for the nations that
obligated them to praise Him?
(a) The RASHBAM (DH a'Gevuros) explains that Hashem constantly does wonders
to the world at large. All people throughout the world benefit from Hashem's
kindness. He keeps the world going, He provides them with sustenance, and so
on. Since they benefit, they should also thank Hashem. How much more so must
*we* thank Hashem, for His kindnesses to us are abundant.
(b) RASHI, though, says that the nations should thank Hashem because they
saw that Hashem did great wonders for *us*. The MAHARSHA expands on this and
says that the wonders which Hashem did for us were done in order to save us
from the plotting of the nations. But if that is true, why should the
nations thank Hashem for those wonders?
The BRISKER RAV (Chidushei ha'Griz Al ha'Torah, Tehilim 117) explains that
there are two different types of Berachos that can be recited on a miracle.
(1) The beneficiary of the miracle thanks Hashem for what he has been given.
This is a "Birkas Hoda'ah," a blessing of thanksgiving. (2) Even if a person
did not benefit from the miracle, when he sees something awe-inspiring, he
praises Hashem and says a "Birkas ha'Shevach," a blessing of praise, such as
when he sees lightning or an awe-inspiring terrain.
The Berachah which the nations make is the second type of Berachah, a
blessing of praise recited when a person sees something awe-inspiring. That
is what the verse means when it says, "Halelu Es Hashem Kol Goyim." The
Gemara says that how much more so must *we* bless Hashem, because besides
saying a blessing of praise at the awe-inspiring miracle, we are also
obligation to recite the other type of Berachah, a Birkas Hoda'ah, since we
are the beneficiaries of that miracle!