1)
Why does it say "they bowed and fell"?
1.
Malbim: This shows the difference between us. They chose inferior means (chariots and horses), and fell. We chose a great matter - Hashem's name, and stood!
2)
What is the meaning of "Kamnu"?
1.
Radak: We were haughty and elevated over them.
3)
What is the meaning of "v'Nis'odad"?
1.
Rashi: We will overpower them, like "Me'oded Anavim" (147:6); it is an expression of Oz (power).