Possible meanings for the word "fortresses" are 1) it refers to Nineveh's fortifications, such as the wall that surrounded the city Alternate translation: "All of your fortifications" or "All of your defenses" or 2) it refers to the fortified cities that were situated along Assyria's borders and prevented enemy armies from attacking Nineveh. Alternate translation: "All of your fortified cities" (See: [[rc://en/ta/man/translate/figs-explicit]])
Nahum compares the ease with which the attackers will conquer Nineveh with the ease with which a person can cause ripe figs to fall from a tree. Alternate translation: "Your enemies will destroy your fortresses as easily as a person can shake a fig tree and eat the first ripe figs that fall" (See: [[rc://en/ta/man/translate/figs-simile]])
This refers to the figs that would ripen first on the tree. These figs fell from the tree easily, so that a person only had to shake the tree to make them fall. Figs that ripened later would require a person to climb the tree and pick them by hand. (See: [[rc://en/ta/man/translate/figs-explicit]])
"if the trees are shaken." This can be stated in active form. Alternate translation: "if a person shakes the trees" (See: [[rc://en/ta/man/translate/figs-activepassive]])
"the figs fall into the mouth of the eater." This is an exaggeration. By saying that the figs fall from the tree into the mouth of the one who eats it, Nahum emphasizes that the figs are ready to eat immediately. Alternate translation: "a person can eat the fig immediately" (See: [[rc://en/ta/man/translate/figs-hyperbole]])