This generalization refers to the kings of the northern kingdoms. Alternate translation: "every king" or "all of the northern kings" (See: [[rc://en/ta/man/translate/figs-hyperbole]])
Possible meanings are 1) this represents ruling over Jerusalem. Alternate translation: "will rule at the gates of Jerusalem" or 2) this represents judging Jerusalem. Alternate translation: "will judge Jerusalem" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Setting their thrones "against all the walls that surround it" represents commanding their armies to destroy the walls surrounding Jerusalem. Alternate translation: "and they will command their armies to destroy the walls surrounding Judah" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Setting their thrones "against all the cities of Judah" represents commanding their armies to destroy all the cities of Judah. (See: [[rc://en/ta/man/translate/figs-metonymy]])