"The Second Coming" by W.B. Yeats is undeniably a great work. The poem is beautifully divided into two stanzas, with the first devoted to commentary on the contemporary world, which remains applicable in the 21st century. The line "the best lack all conviction" skillfully describes the current state of affairs.
The second stanza reads more like prophecy than poetry. In my opinion, Yeats is referring to the second coming of Christ after the arrival of the Sphinx in the world. According to Greek mythology, the Sphinx brought nothing but destruction and famine. The arrival of Jesus Christ to save the world from this destruction (symbolized by the Sphinx) is quite justifiable. However, the flow and power of Yeats' words go beyond mere description.