Here "Its quiver" represents the enemy nation's army, and the arrows in the quiver represent the soldiers in the army. (See: [[rc://en/ta/man/translate/figs-metonymy]])
An open tomb is one that is prepared to have many dead bodies put in it. The enemy army will kill many people. AT: "That nation's army will use their arrows and kill many people" or "Because of the arrows of its army, many people will die and be buried" (See: [[rc://en/ta/man/translate/figs-simile]])
# So your harvest will be consumed, your sons and daughters also, and your food
Possible meanings are that 1) their harvest and their food that was for their sons and daughters would be consumed. AT: "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. AT: "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]])
# So your harvest will be consumed
This can be translated in active form. AT: "So the army of that nation will eat the food that you expected to harvest" (See: [[rc://en/ta/man/translate/figs-activepassive]])
# your sons and daughters also, and your food
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 batter down with a sword your fortified cities
The sword is a synecdoche for all of the different weapons that people use in war. AT: "They will use their weapons to conquer your strong cities that you trusted to protect you" (See: [[rc://en/ta/man/translate/figs-synecdoche]])