en_tn_condensed/jer/51/53.md

her highest fortresses ... to her

The people of Babylon are spoken of as if they were the city itself, and the city is spoken of as if it were a woman. Alternate translation: "their highest fortresses ... to them" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-metaphor)

even if Babylon went up to the heavens or fortified her highest fortresses

This is a hypothetical situation that will never heaven. God said this to assure Israel that it does not matter how strong Babylon might be; God will destroy Babylon. (See: rc://en/ta/man/translate/figs-hypo)

destroyers would come from me to her

This can be expressed with God as the subject. The word "her" refers to Babylon. Alternate translation: "I would send destroyers to her" or "I would send enemies to destroy Babylon"