1)
Why does it say "Teshivenu Achor"?
1.
Rashi: Future tense is used in place of present (You turn us back).
2.
Radak: If we will stand against them when they come to harm us, we have no strength. When You do not help us, it is as if You turn us back.
3.
Malbim: Also when we would have won based on nature, You helped the afflicter and turned us back.
2)
What is the meaning of "Shasu Lamo"?
1.
Rashi: Each [enemy soldier] took spoils for himself.
2.
Radak: This is like "v'Hemah Shosim Es ha'Geranos" (Shmuel I, 23:1). They took our money for themselves.
