These lines have been taken from Walt Whitman's famous poem 'Song of Myself' that was included in his poetry collection 'Leaves of Grass'. As these lines suggest, the poem is about the celebration of individual self as reflected by the words 'I celebrate myself' and unanimity of human soul when he says 'every atom belonging to me as good belongs to you'. The poet is celebrating the democracy, identification of his self that he associates to the universal self ('what i assume you shall assume'). Thus, these are the words by Walt Whitman who takes a dig to embrace the individuality(the title 'song of myself' itself suggests) and its every sate along with the glorification of democracy by associating his individual self in a universal context.
