The word "sword" here represents war or an army that attacks. Alternate translation: "There will be war against Egypt" or "An enemy army will attack Egypt" (See: [[rc://en/ta/man/translate/figs-metonymy]])
The abstract noun "anguish" can be expressed in terms of how the people feel. Alternate translation: "the people of Cush will be very sad" or "the people of Cush will suffer" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
This can be translated in active form. Alternate translation: "when the attackers destroy the foundations of the buildings in Egypt" (See: [[rc://en/ta/man/translate/figs-activepassive]])