This verse finishes the prayer that the writer wants his audience to pray. He asks them to speak directly to the city of Jerusalem, as if the city was a person who could hear them. (See: [[rc://en/ta/man/translate/figs-apostrophe]] and [[rc://en/ta/man/translate/figs-personification]])
These two phrases have the same meanings and are used together to strengthen each other. Alternate translation: "May the people in Jerusalem live in peace" (See: [[rc://en/ta/man/translate/figs-parallelism]])
Here Jerusalem is referred to by the fortress walls that protects it. The terms "walls" and "fortress" refer to the same thing. Alternate translation: "within Jerusalem" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-parallelism]])