In "Do Not Go Gentle into that Good Night," what effect do the repetitions create?

The repetition of the first and third lines of the poem impress the reader with the speaker's relative desperation that his father fight against death (we learn the narrator of the poem is speaking to his or her father in line 16). It sounds as though the speaker is trying to persuade his or her father that, although continuing to live might be painful or difficult, resisting death is the best thing, the right thing,...

The repetition of the first and third lines of the poem impress the reader with the speaker's relative desperation that his father fight against death (we learn the narrator of the poem is speaking to his or her father in line 16). It sounds as though the speaker is trying to persuade his or her father that, although continuing to live might be painful or difficult, resisting death is the best thing, the right thing, to do. The speaker repeats these lines in the context of describing all different kinds of men—wise men, good men, wild men, and serious men (or men who are very near death, since "Grave" has two potential meanings here)—and all the different reasons that they choose to stay in "the light." This seems to be an attempt to convince the father that no one else goes "gentle into that good night," so neither should he.