What does this passage means?

This appears in a letter attributed to Chief Sealth (aka Chief Seattle) addressed to President Franklin Pierce, and it may or may not be genuine.

Its intent is to register Chief Sealth's distrust in the U.S. government's policy toward America's indigenous peoples.

I think it is a philosophical observation regarding the difference between the value systems of European-descended white Americans and native Americans--that is, whereas whites placed abstract economic concerns above all others, Indians had a more holistic and practical worldview.

That is, whites, regarding the Earth as a commodity to be bought and sold, and nature as something to be subdued and civilized, separated themselves from the natural world.

On the other hand, Sealth believed that since humans originated from nature like everything else on Earth, they were intricately connected with it. Nature wasn't something outside and separate from his world; it was his world.

Therefore, he considers that--as nature comprises the whole of existence--it is impossible to step outside nature. Whites' efforts to conquer the land and force it to do their bidding were therefore futile. He believes that, in harming the environment, humans harm themselves.

Mostly, though, I think he just didn't want his people to be forced off their land. (Of course, the Suquamish were eventually relocated to a reservation by means of one of those U.S. government treaties.)

It is very confused, clumsy and clichéd but what is seems to be getting at is an idea of predestination and that no one's life is in isolation of all others.