Poetry has been part of Pagan spirituality since the beginning of religion, the beginning of poetry, and likely the beginning of spoken language. There is something truly holy about words that are offered in honour of the Divine. Many spell-workers have also found that words have extra effect when selected to produce rhythms and rhymes.
Poetry was an important way of passing on knowledge in the times before written language. In Celtic culture Druids spent years memorizing long poems as part of their basic training. We see this even today — William Dalrymple’s book “Nine Lives” documents examples such as illiterate healers near Pabusar in northern India who recite the four-thousand-line Epic of Pabuji from memory. Even when poetry becomes formalized through writing it can become the core way of transmitting myth and religion. Greek religion for instance was passed on through the generations through the written poetic works of literate scholars such as Homer, Sappho, and Euripides. The oldest known written poetry is likely the work of Enheduanna, who lived around 2300 to 2225 BCE. Betty De Shong Meador’s book “Inanna, Lady of Largest Heart” is probably the best book out currently on the topic of Enheduanna and her poetry. Look for Diane Wolkstein & Samuel Noah Kramer’s “Inanna: Queen of Heaven and Earth” for another good example of ancient poems and hymns from Sumer. Another really old surviving Divine poem is the Epic of Gilgamesh written around 700 BCE.
In more modern times practicing occultists such as William Bulter Yeats and Aleister Crowley expressed their spiritual ideas through poetry. Yeats’ work is examined in relation to his occult practice in “W. B. Yeats – 20th Century Magus” by Susan Johnston Graf. You can also read more about Yeats’ life and work at sites such as http://www.online-literature.com/yeats/ Crowley’s work is similarly examined in Charles Richard Cammell’s “Aleister Crowley: The Man, The Mage, The Poet” and on websites such as http://www.poemhunter.com/aleister-crowley/
Poetry has had an important role in the history of modern Paganism in the English speaking world. In 1948 the poet Robert Graves published his inspired book “The White Goddess” and it hit the occult and alternative spirituality community like a bombshell. That one book encouraged countless seekers to turn to their roots and embrace ancient Pagan deities in a way that few other books have. Graves has admitted that while the book was written in the style of a scholarly text it was actually a poetic whole that sprang from his heart and soul over a three week period in January 1944. While the history it contains is more speculative than scholarly it still serves as an amazing poetic Pagan bible.
Since then all sorts of overtly Pagan poetry has been published. Among my favourite collections are “Life Prayers” and “Earth Prayers” edited by Elizabeth Roberts & Elias Amidon, “Earth Poems” edited by Ivo Mosley, “The Pagan’s Muse” edited by Jane Raeburn, and the recently published “Datura” edited by Ruby Sara. Some books present primarily the work of a single poet. I really like “Charge of the Goddess” by Doreen Valiente, “Thorns of the Blood Rose” by Victor Anderson and Gwydion Pendderwen, “Dewdrops in the Moonlight” by Shanddaramon, and for a more Crowleyite feel try “Qutub” by Andrew Chumbley.
If you are interested in trying your hand at writing Pagan or magickal poetry you can’t go wrong with the helpful guidebook “Composing Magic” by Elizabeth Barrette. And if you want to go the extra step and pursue becoming a holy poet or bard, look for “The Bardic Handbook” by Kevan Manwaring. They will really inspire you.