In Walt Whitman's poem "Song of Myself," lines 7-16 introduce several important themes that will reoccur frequently. For instance, when Whitman references the many past generations of family members that led to his birth (7), he illustrates the countless and myriad generations of humanity that are distilled down in the present generation. This theme will become important later on, as it allows Whitman to explore the multiplicity inherent in each individual. Furthermore, when Whitman references "creeds and schools in abeyance" (10), he touches on the many differing beliefs and ideas at work in the world, which will again be an important addition to his discussion of multiplicity throughout the poem. Finally, Whitman's description of smelling many perfumes (14-16) is a precursor to his later mission to inhale and swallow as many different experiences as possible. Additionally, his discovery of a personal trait special to him (15) is key, as it suggests that an intimate knowledge of oneself is only possible through this process of participating in myriad and diverse experiences.
With this context in mind, section 52 becomes a very fitting conclusion indeed. The image of the swooping hawk (1331) ultimately drives Whitman to declare that he is "not a bit tamed, I too am untranslatable" (1332). Whitman only comes to this conclusion after thoroughly exploring how much multiplicity (how many generations of humanity, how many "creeds and schools") he himself encompasses. He then goes on to say "the last scud of day holds back for me,/ It flings my likeness after the rest and true as any on the shadow'd wilds" (1334-5). After understanding the inherent multiplicity of existence and experience, Whitman imagines himself extending to infinite proportions and dispersing throughout the landscape. This dramatic conclusion is set up by Whitman's original musings on multiplicity, identity, and experience in the first lines of the poem, which is why it's such a satisfying ending.