In paradise, when thou were born in the first rose, beneath the tree of knowledge thou receivedst a kiss and thy right name was given thee thy name poetry why does the narrator use a metaphor comparing the phoenix to poetry ?

Poetry is something that historically has been reborn over and over and over, depending on what's happening in the world. The way that themes, styles, and forms of poetry have changed based on time period, religion, leadership, viewpoints towards the world, etc, is similar to the way a phoenix is reborn again and again.