Why should the nations bless our G-d?
Rashi: It is for His wonders - He kept us alive in Galus, and they cannot destroy us. Radak - Yisrael will tell nations to bless Hashem for this reason.
Pesach Einayim (Pesachim 118b 1 ): They plot many decrees against Yisrael, and often Hashem nullifies them, and Yisrael never find out. Their officers recognize His protection over us more than we do!
Malbim: Not only does He oversee nations in general, rather, even over individuals.
He explained "Halelu Es Hashem Kol Goyim
Why does it say "v'Hashmi'u Kol Tehilaso"?
Malbim: It depicts the praise as a tangible matter that emits a voice of praises of Hashem. Announce this to the Rabim!
