What do lines 7-16 suggest about the theme of Whitmans long multi part poem

Much has been said about the end of "Song of Myself" here. It is true that Whitman is asserting his essential unity with everything, not just nature. From the beginning of the poem he asserts his union with his reader:

I Celebrate myself, and sing myself, And what I assume you shall assume, For every atom belonging to me as good belongs to you.