The speaker calls the imminent revelation in stanza 2 the "Second Coming." Usually, the term Second Coming refers to the return of Jesus Christ. This event will usher in, according to the biblical book of Revelation, the joining of heaven and earth in a glorious kingdom of light and love, where all tears will be wiped away, and God himself will walk among the people.

However, the Second Coming that Yeats's speaker sees as imminent is a terrible reversal of that. Instead of the triumphant return of Christ as the lamb of God, the speaker foresees a "beast" heading towards Christ's birthplace in Bethlehem after "twenty centuries of stony sleep." This half lion, half man has a "gaze blank and pitiless." He is associated with darkness and "nightmare."

All of this is an expression of Yeats's idea that history comes in "gyres" or wide circles. He believed that with the end of World War I, a more frightening period was being born as the Christian cycle wound down.

The poem reflects the trauma many Europeans suffered as a result of World War I, which shattered their confidence that the world was progressing towards a more civilized future. The poem was interpreted, too, after the rise of Hitler, as foretelling his appearance as a "pitiless" beast representative of a new age.