The word "They" refers to the people who trust in chariots and horses. This can be stated in active form. Alternate translation: "God will bring them down and make them fall" (See: [[rc://en/ta/man/jit/figs-activepassive]])
"we will get up and stand up straight." These two phrases mean basically the same thing. Both of these stand for victory in battle. (See: [[rc://en/ta/man/jit/figs-doublet]])