William Wordsworth wrote a great deal in poetry and in prose about the effect of the natural world on his heart and mind. Many of Wordsworth's writings make large, complex claims for the moral and spiritual influence of nature, but some of his most popular poems are short lyrics which describe his response to nature in the simplest of language. "My Heart Leaps Up When I Behold" is one of these. The poem consists of nine rhymed lines whose meter ranges from dimeter to pentameter.
Wordsworth's main message in this poem is that a simple response of "natural piety" upon seeing a rainbow is something that has remained with him throughout his life, and the same source of joy is likely available to the reader. One may not see rainbows very often, but there is always some aspect of nature to be enjoyed. Even in a city, one can see the sky. More crucially, the most important aspects of life do not change with age, and the love of nature always provides a connection to one's childhood. The famous—and famously paradoxical—line "The Child is the father of the Man" reinforces this idea that one's childhood joys and fascinations remain influential to one's adult self.