The poem is an example of apostrophe, addressing Death (personified) as a living being who is thus listening to the speaker. This intentionally removes the mystery or sense of superiority in the concept of death, making it seem as though death can be easily defeated.
Allusion is used in the final line. 1 Corinthians 15:26 states, "The last enemy to be destroyed is death." This both echoes the sentiments of the poem, nothing that Death is the enemy of humanity, and that Death has no power itself. Ultimately, those who believe in Christ will defeat Death through salvation and eternal life. The speaker of this poem notes that death is simply a "short sleep," after which "we wake eternally / And death shall be no more."
A paradox is established in these lines:
For those whom thou think'st thou dost overthrow
Death thinks it it possible to "overthrow," or end the lives of, humanity. Another way to rephrase this would be "The people you think you have killed are not dead ." This paradox...
(The entire section contains 3 answers and 1072 words.)