Wilbur is concerned with linking our everyday lives to the greater spiritual world. His poetry is not religious, but it investigates human existence, and all the beautiful, wonderful, sometimes messy stuff that comes with. His poetry celebrates our ability to experience moments of transcendence and glory in our everyday lives.
Also, sidenote: dude loves him some puns. So if you find a bunch of them in a poem, you just might be reading Wilbur.