Song of Myself (1892 version) by Walt Whitman

Explain what this part of the poem means: There is that in me—I do not know what it is—but I know it is in me. Wrench’d and sweaty—calm and cool then my body becomes, I sleep—I sleep long. I do not know it—it is without name—it is a word unsaid, It is not in any dictionary, utterance, symbol. Something it swings on more than the earth I swing on, To it the creation is the friend whose embracing awakes me. Perhaps I might tell more. Outlines! I plead for my brothers and sisters. Do you see O my brothers and sisters? It is not chaos or death—it is form, union, plan—it is eternal life—it is Happiness.