What is the meaning of "ha'Kel Lanu Kel l'Mosha'os"?
Rashi: Kel saves us.
Malbim: The strength of salvations are found in Him - this is only for us.
What is the meaning of "velEi'lokim Hashem la'Maves Totza'os"?
Rashi: He has ways to lead to many kinds of deaths (but not for us, rather, for His enemies - verse 22).
Radak: He has many ways to carry out verdicts of death for His enemies and to eradicate them. E.g. He drowned the Egyptians in Yam Suf and sent 10 Makos, and sent hailstones against the kings of Kena'an, or made frenzy among the enemies to strike each other, e.g. among the Pelishtim - "Cherev Ish b'Re'ehu Mehumah Gedolah Me'od" (Shmuel I, 14:20). He also sent the Makeh of Techorim and Achbarim 1 , and many other Makos.
Malbim: Totza'os are the borders of where death dwells; past the borders is of Hashem. It is as if death has special lands, i.e. Chutz la'Aretz; it does not rule in Eretz Yisrael, which is of Hashem.
Rashi (Shmuel I, 5:6, based on Midrash Shmuel 10:4): Techorim is hemorrhoids, an affliction of the anus. A mouse rose from the depth and removed his innards, and returned to the depth.
