Tao Te Ching: Chapter 7
Heaven is long-enduring and earth continues long. The reason why heaven and earth are able to endure and continue thus long is because they do not live of, or for, themselves. This is how they are able to continue and endure.
Therefore the sage puts his own person last, and yet it is found in the foremost place; he treats his person as if it were foreign to him, and yet that person is preserved. Is it not because he has no personal and private ends, that therefore such ends are realised?