“Thou”

Given that the speaker directly addresses Death in this poem, it isn’t surprising that the second-person pronoun should have such a prominent place. But what is surprising is the speaker’s choice of second-person pronoun. In modern English, the only pronoun we have for the second person is “you.” In Donne’s time, however, two forms of second-person address were available: “you,” which was used in circumstances requiring formality, and “thou,” which was familiar and hence informal. The fact that the speaker uses the familiar form to address Death is significant, since it implicitly diminishes the sense of Death’s power. If Death were really as “mighty and dreadful” as people seem to believe, then it would make sense to address this figure with a cowering formality. But the speaker’s whole point is to refuse Death. As such, their use of “thou” serves as a rhetorical gesture of deflation. What’s more, the speaker doesn’t just use “thou” once in the poem. Indeed, they use it again and again—ten times, if we include the forms “thee” and “thy.” This repetition has a cumulative effect that subtly, but consistently, puts Death in its place.

Negation

For a work premised on contradicting the power of Death over life, it’s appropriate that Donne’s poem makes frequent use of negation. This rhetorical tactic occurs most prominently in the opening quatrain, where the speaker insistently negates received ideas about Death (lines 1–4):

     Death, be not proud, though some have called thee
     Mighty and dreadful, for thou art not so;
     For those whom thou think'st thou dost overthrow
     Die not, poor Death, nor yet canst thou kill me.

Here, the speaker commands Death not to indulge in pride, for it isn’t as all-powerful as some believe. Those whom Death presumably kills actually don’t die, which means that Death also can’t kill the speaker. The sustained use of negation in these four lines rhetorically cuts Death down to size. After the refusals of the opening quatrain, the speaker sets aside the tactic of negation until the poem’s end, where they revive it in the closing couplet (lines 13–14):

     One short sleep past, we wake eternally
     And death shall be no more; Death, thou shalt die.

The speaker again uses a negative statement to dispel the idea of Death’s power over life. However, after using a negative statement in the first half of the final line, the speaker reformulates the same idea in the second half, this time in positive terms. This rhetorical shift from a negative to a positive statement enables the speaker’s shocking conclusion. That is, the very fact that “death shall be no more” means that Death itself “shalt die.”