Donne's speaker announces his own death before the first line is even over: "This is my play's last scene." From there the sonnet is a countdown. It is about the moments before dying, and its central idea is a tidy, frightened sorting. The body goes to earth, the soul to heaven, and the sins to hell, which leaves the speaker clean enough to ask God to count him righteous.
The opening four lines pile up images of finishing, each smaller than the last. Life is a play, then a pilgrimage, then a race, then a "span" (a hand's-width measure), and finally a single "point" of time. "Last" keeps returning, and "latest" completes the run, so the sentence seems to be running out of road as we read it. "Idly, yet quickly run" has a sting in it: a life both wasted and over in a flash. The speaker looks back at a race he barely took seriously, and nothing about the picture is grand.
Then death arrives, and Donne makes it physical. Death is "gluttonous," a creature that eats, and it will "unjoint" body and soul, a word that suggests carving a carcass or taking furniture apart. The sleep that follows lasts only "a space," a brief pause, before the "ever-waking part" sees "that face." God is never named, which makes the face more frightening, and the fear is felt in the body: it "shakes my every joint." The word echoes "unjoint" from four lines earlier, so the body that death is about to take apart is already trembling to pieces. The rhyme reinforces this. "Appoint," "point," "unjoint" and "joint" all share one sound and frame the octave like a lid, leaving no way out of the fear before the poem turns.
The turn comes at "Then," and the sestet changes tone. The syntax becomes a balanced, almost legal pairing: *as* the soul flies to heaven and the "earth-born body in the earth shall dwell," *so* the sins fall to hell. Each of the three gets "their right," a phrase that sounds like bookkeeping. The idea is oddly dark. Sins are treated as things with a home, the place where they were "bred," and the speaker hopes to be freed of them by sending them back there. The neatness is a way of staying calm, as if a clear enough list might make dying manageable.
The couplet shows the limits of that calm. "Impute me righteous" is an imperative, but it is a plea, not a boast. To impute is to credit righteousness to someone who has not earned it, so under the arithmetic lies a request for mercy. The speaker cannot finish the sorting alone. The last line, "the world, the flesh, the devil," is a well-known triple of Christian temptations. It ends flatly on the rhyme of "evil" and "devil," like a door shutting on a list.
The form helps the effect. The rhyme scheme is ABBAABBA CDCD EE, a Petrarchan octave followed by a sestet that tightens into a couplet. The metre is iambic pentameter, but it often sounds like urgent speech. The first line, with its run of heavy syllables ("this is my play's last scene"), lands like a verdict.
What makes the poem significant is this friction between control and terror. The sonnet is a form often associated with love, and here it holds one of the largest subjects there is, a person's own death, in fourteen controlled lines. The control is not the whole story, because the trembling joints sit in the middle of the poem and the final plea is a request, not a certainty. Donne lets us see someone trying to organise his dying into order, and not quite managing it. That honesty, and the way sound and image carry it, is why the poem still feels immediate.