How does Maulana Jalial al-Diin Riumii use imagery in The Essential Rumi?

Riumii often blends daily life and attendant metaphors along with divine imagery. In the poem, Jesus on the Lean Donkey, for example, he begins by explaining that Jesus the Christ riding atop of a hearty but simple beast of burden is akin to the rational mind in its relationship to the animalistic nature of mankind. Rumi calls it the "animal soul". This leads into a story, that may be true or false, of how a man is healed by rough and thorough discipline.