The Rubaiyat is not a single argument but a garland of quatrains, each a self-contained four-line poem that FitzGerald loosely arranged into a day's meditation. It opens at sunrise, with morning flinging the stone that puts the stars to flight and a voice in the tavern crying to fill the cup before life runs dry. From the first lines the reader is told how little while we have to stay, and that once departed we may return no more.
The early quatrains gather the poem's signature images: the cup and the vine, the nightingale and the rose, the bird of time already on the wing. The speaker invites a companion to a strip of grass between the desert and the sown, with a loaf of bread, a flask of wine, a book of verse, and someone beside him singing, and declares that this is paradise enough. Against worldly ambition and the promise of a paradise to come, he counsels taking the cash in hand and letting the credit go.
The mood then darkens into reflection on time and ruin. The worldly hope men set their hearts upon turns to ashes, or it prospers and is gone like snow on the desert's face. Great kings abide their hour in a battered caravanserai whose doorways are night and day, then leave. The grain hoarded and the grain scattered come to the same dust, and the rose that opens this morning will soon close, taking the singer with it.
At its core the poem turns to fate and the silence of the divine. Destiny plays at chequers with men for pieces; the ball goes right or left as the player strikes; the Moving Finger writes and cannot be lured back. The inverted bowl of the sky offers no help. The speaker even asks the maker who set snares along his road not to charge his fall to sin, pressing the problem of a world that seems both designed and indifferent.
The sequence ends without resolving the riddle and chooses, instead of an answer, an attitude. In the Potter's shop the clay pots themselves debate their maker and their end. The speaker asks to be buried by a garden side, his ashes still fragrant with the vine, and closes on a quiet, human note: when the friend who outlives him passes the spot where he once sat among the guests, let her turn down an empty glass in his memory.