Great evil is great good. This sentence is also an allusion, but it is a Buddhist allusion. It is said that the Buddhist Bodhisattva Samantabhadra was a butcher-like killer before becoming a Buddha, killing people in several cities. Later, the clouds in the sky presented the Tathagata method. Pu Xian looked back and realized heaven and earth. He immediately sat cross-legged on the ground and became a Buddhist. This is famous. He put down the butcher knife and became a Buddha!
When he was killing people, until one day, he gave up killing people. That saved many people, many people who would have been killed by him. In this state, his kindness is unparalleled, because putting down the butcher's knife is to save all beings.