Heaven and earth are heartless: benevolence, that is, the so-called love of Confucianism, here refers to private love and preference. Heaven and earth are heartless, that is to say, heaven and earth have no preference. Laozi believes that heaven is inaction, that is, it conforms to nature. Everything in heaven and earth operates according to the laws of nature, and there is no master who dominates nature. Heaven and earth are only natural objects of matter, and they don't have a preference for one thing and an aversion to other things as theologians imagine.
(2) Grass dog: a dog made of grass for sacrifice. When people make grass into straw dogs, they have no preference or concern for it; Not hate or despise it, but throw it away after sacrifice. Heaven and earth regard everything as a grass dog, which means that heaven and earth have no selfish love for everything and let it naturally generate or destroy. In the later period, the sage was heartless, which means that the sage didn't care about the people and let them take care of themselves.