i cant help you with the evidence part but,
using figurative language is an effective way of communicating an idea that is not easily understood because of its abstract nature or complexity. although figurative language does not offer a literal explanation, it can be used to compare one idea to a second idea to make the first idea easier to visualize. figurative language also is used to link two ideas with the goal of influencing an audience to see a connection even if one does not actually exist. writers of prose and poetry use figurative language to elicit emotion, help readers form mental images and draw readers into the work.
i hope that helps some..