Here the word "city" represents the people who live in the city. Mockers causing the people to experience turmoil and possibly to become violent is spoken of as if they set the city on fire. Alternate translation: "create turmoil for the people of a city" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])
This idiom means to cause angry people no longer to be angry. Alternate translation: "calm the wrath of angry people" (See: [[rc://en/ta/man/translate/figs-idiom]])