These lines that Margo highlights are from Walt Whitman’s famous poem "Song of Myself." They emphasize the transcendentalist beliefs that humans beings are connected to nature and that the death of the human body is therefore not a true end to life.

Consider the first line: “I bequeath myself to the dirt to grow from the grass I love.” Here the speaker firmly states that he will leave his own self and become one with the Earth beneath him and grow from the ground. The word “love” here suggests he has no hesitation about this and almost implies a hint of excitement. The casual and almost anticipatory nature with which the poet states this suggests that humans should embrace their inherent unity with nature.

The speaker playfully reinforces this notion with the next line: “If you want me again look for me under your boot-soles.” Here the speaker also suggests that when people are gone from the human world, they are not really gone, because humans are one with nature. This prompts the reader to reflect on the notion of connections between humans and how people who leave you physically might still always be with you. The passages Quentin reads from "Song of Myself" help guide him throughout and after his search for Margo. They help him remain optimistic about connections between human beings.