en_tn_condensed/jos/01/18.md

rebels against your commands ... disobeys the words you have commanded them

These two phrases mean basically the same thing and emphasize that any form of disobedience will be punished. (See: rc://en/ta/man/jit/figs-parallelism)

will be put to death

This can be stated in active form. Alternate translation: "we will put to death" (See: rc://en/ta/man/jit/figs-activepassive)

be strong and courageous

Israel and God considered both traits important for Joshua to pursue as their leader. (See: rc://en/ta/man/jit/figs-parallelism)