This sentence comes from the fifth chapter of Laozi's Tao Te Ching. Benevolence here is kindness, kindness and kindness to people. Straw dogs is a kind of dog tied with grass. In the past, a grass-tied dog was used as a sacrifice instead of a live dog. After the sacrifice, it was discarded as waste. The whole sentence means that heaven and earth have no sense of likes and dislikes, and they have no mercy on everything and let it die.