Yeats uses many different literary devices in his poem "The Second Coming." One that is a hallmark of his poetic style is half-rhyme, which we see in "gyre/falconer" and "hold/world". He uses many metrical variations, especially initial trochaic substitutions. He uses alliteration in several places, most dramatically in "beast ... Bethlehem ... born" and "darkness drops". The end of the poem is technically a rhetorical question. There are several places in the poem where Yeats uses metaphor , especially in the opening:
Turning and turning in the widening gyre
The falcon cannot hear the falconer;
where the falcon stands as a metaphor for humanity which has lost its direction and is unable to "hear" the voice of the divine. The figure of the beast which heralds the Biblical apocalypse is also used metaphorically by Yeats in this poem.
The title of Yeats' poem, "The Second Coming," is a Biblical allusion to the return of Christ in the Book of Revelations and the judgment of man. Particularly in the second and final stanzas of the poem, Yeats also references the rise of the Antichrist and the beast, two figures who are prophesied to rise during the Great Tribulation, especially in the final lines "what rough beast, its hour come round at last,/ Slouches towards Bethlehem to be born?"
Yeats uses the metaphor of sleep in these lines:
The darkness drops again but now I know
That twenty centuries of stony sleep
Were vexed to nightmare by a rocking cradle,
to compare the two thousand year span of time between Christ's original appearance and the second coming. Yeats' metaphor reveals that the 'sleep' has been uneasy through his diction and the use of the word "stony" which has the connotation of hardness and general lack of comfort.
Yeats uses the falcon in the first stanza as a symbol for order and civilization. Falconry was a genteel practice, usually for noblemen, in the Middle Ages, but the fact that the falcon can no longer hear the falconer suggests a disruption in the connection between man and nature. Moreover, the lack of connection between the two reinforces the speakers' belief that "things fall apart" and the old traditions of man, like falconry, have no place in these new turbulent times.