Possible meanings are that 1) their harvest and their food that was for their sons and daughters would be consumed. Alternate translation: "So your harvest and your food for your sons and daughters will be consumed" or 2) their harvest, sons and daughters, and food would all be consumed. The idea of the sons and daughters being "consumed" would be a metaphor for killed. Alternate translation: "So your harvest and your food will be consumed, and your sons and daughters will be killed" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This can be translated in active form. Alternate translation: "So the army of that nation will eat the food that you expected to harvest" (See: [[rc://en/ta/man/translate/figs-activepassive]])
Possible meanings are that 1) the enemies would eat the food that the sons and daughters should eat, or 2) the enemies will destroy the sons and daughters and eat the food.
# They will eat
The word "They" refers to the army of that nation.
# They will beat down with a sword your fortified cities
The sword is a synecdoche for all of the different weapons that people use in war. Alternate translation: "They will use their weapons to conquer your strong cities that you trusted to protect you" (See: [[rc://en/ta/man/translate/figs-synecdoche]])