Mahmoud Darwish’s poem “The Horse Fell Off the Poem” is contained in his 2003 collection Don’t apologize for what you did and can be found translated from the original Arabic into English in the collection The Butterfly’s Burden: Poems. Darwish’s poem prominently features imagery of nature and love, like this couplet mentioning white doves (a symbol for lovers):
A pair of white doves
chatting on the branches of a holm oak
At the same time, language of warfare and battle can be found throughout the poem: for example, it states that love poems “guard” the moon, and the speaker is said to “attack and retreat.” Even the horse referenced in the first line ultimately falls “bloodied” in the final stanza and thus might be understood as a horse of battle.
Essentially, Darwish’s mixture of the imagery of nature and love (the moon, doves) on one hand and imagery of battle and warfare on the other reflects a long-standing conflict he faced as a poet. Throughout his career, Darwish wrote with first-hand knowledge of the Israeli-Palestinian conflict. In fact, he even served on the board of the Palestinian Liberation Organization. Naturally, the conflict he witnessed and was involved in is reflected in his poetry. At the same time, Darwish was drawn to literary tradition and to an urge to express broad human themes, like love. He expressed this inner struggle in a quote reprinted in The Butterfly's Burden:
The creative person must create his flexible margin between the patriotic, the political, the daily, the cultural, and the literary. But what am I to do? What does a poet do in the executive council? Will I be able to write a book of love when color falls on the ground in autumn?
By colliding these two aspects of his interests in “The Horse Fell Off the Poem,” Darwish created a poem that is “metapoetic,” meaning it is a poem about poetry. Yet its vivid imagery makes the experiences of intimate love and of public conflict seem all the more poignant for the collision.
To answer the second part of your question: the poem repeatedly uses a literary device known as chiasmus that underscores this collision of opposing forces. “Chiasmus” comes from the Greek word meaning “crossing” or “shaped like the letter X.”
In poetry, chiasmus refers to instances where phrases are repeated in reverse order: if you drew lines connecting the parts of the poem that repeat, you would end up with something shaped like the letter X. The following lines are a good example of chiasmus:
The two absent ones: you and I
you and I are the two absent ones
Another example of chiasmus can be found at the end of “The Horse Fell Off the Poem”:
The horse fell bloodied
with my poem
and I fell bloodied
with the horse’s blood ...
This example shows that chiasmus is not always a word-for-word repetition: the crossing involves one set of phrases devoted to the horse (“the horse fell bloodied” to “the horse’s blood”) and another devoted to the speaker (from “my poem” to “I fell”).