Why would a speaker use rhetoric?

to tell a story
to show similarities
to effectively persuade
to show differences

Weave a circle round him thrice, and close your eyes with holy dread, for he on honeydew hath fed, and drunk the milk of paradise. which sound device is used in these lines from “kubla khan” by samuel taylor coleridge to emphasize the amazement the speaker expects people to feel if he is able to build a dome of air? the consonance between “close” and “eyes” the consonance between “drunk” and “milk” the alliteration between “honeydew” and “hath” the assonance between “close” and “holy”