Alliteration, the placing of words beginning with the same consonant in close proximity, creates a sense of rhythm throughout the poem and adds emphasis to important words, most notably in the refrain.

We find alliteration in the hard gs of "do not go gentle into that good night," which places a particular emphasis on "go" and "good." The repetition of "rage, rage," in the refrain is also alliterative. Together with the force that the repetition provides, the alliteration focuses the reader's attention on the important words "rage, rage": we understand the speaker's passionate conviction that his father should fight against dying.

Other examples of alliteration are "sang the sun," and "learn, too late," which add more—and a gentler—rhythm and cadence to the poem, reflecting a quiet moment in the verse.

Assonance does not appear much in the poem, unless we consider the "a" sounds in stanza one in "and," "at," and "against," but in reality, it is the alliterations that drive the emotional force of the poem.

Personification shows up in stanza three, in which "deeds," an abstract concept, is given the human quality of fragility and also said to "dance," adding a sense of beauty and worth even to the quiet acts of good men.

Throughout the poem, "that good night" is a metaphor for death, a way of comparing death to darkness and sleep. The "good" is ironic: the speaker doesn't want his father to capitulate to any notion of death as good.

The poem gains its power from the alliterative words it hurls against the concept of death, encouraging all old men to fight back and not give in. Night works well as a metaphor because we can visualize and understand fighting not to get sucked into darkness.