I will set my face against you

This idiom means he "firmly decided." Alternate translation: "I have made up my mind to oppose you" (See: rc://en/ta/man/jit/figs-idiom)

you will be overpowered by your enemies

This can be stated in active form. Alternate translation: "your enemies will defeat you" (See: rc://en/ta/man/jit/figs-activepassive)