"I have been extremely jealous for Jerusalem and for Zion." Yahweh does not want anyone to harm Jerusalem or try to have Jerusalem love anything more than Yahweh.
# jealous
Here this word refers to Yahweh's strong desire to protect his people.
# Jerusalem ... Zion
These are a metonyms for the people who live in Jerusalem and Zion. Alternate translation: "the people of Jerusalem ... the people of Zion" (See: [[rc://en/ta/man/jit/figs-metonymy]])