In other words, no matter what anything becomes, it is the behavior of the thing itself (including luck), which has nothing to do with heaven and earth; Heaven and earth let nature take its course, and everything is like the night wind, moistening things silently.
A detailed explanation of "Heaven and Earth are unkind to all things";
"Grass dog" is a dog made of grass during ancient sacrifices. "Be a dog, use it as a sacrifice, and then abandon it." Interestingly, the treatment of this pig before and after the sacrifice was very different: before the sacrifice, people were in awe of it and even dared not touch it; After the sacrifice, the pig was thrown aside and trampled, and people didn't even look at it.
Literally, it is easy to interpret God as unkind, but after analyzing the context, we can find that Lao Zi doesn't mean it at all. What it really means is that there is no love or preference between heaven and earth, and everything is treated like a straw dogs, which is allowed to grow naturally until death. This is just another explanation of Laozi's thought of "natural inaction". No interference, completely independent.
The same is true of the last sentence: saints are also unreasonable, or they love everyone equally and let people take care of themselves, without giving guidance or hitting. This embodies the advanced thought of equality of all beings. In that era when slavery was still deeply rooted, it was admirable that Laozi could shout the slogan of equality and fraternity among all beings. Later, Lao Tzu gave an example to illustrate the first two points.