Whitman had many themes in his poetry; these are only a few.

For example, in section 48 of “Song of Myself”:

I have said that the sould is not more than the body
And I have said that the body is not more than the soul,
And nothing, not God, is greater to one than one’s self is,
And whoever walks a furlong without sympathy walks to his own funeral drest in his shroud
….
And I say to any man or woman, Let your soul stand cool and composed before a million universes.