When Genghis Khan educated his descendants on the way back from the Western Expedition, which famous saying showed the cultural level of Mongolia at that time?

He once said a famous proverb: "The greatest pleasure in life is to kill the enemy completely, take all their property, watch their relatives cry, ride their horses and rape their wives and daughters." All the people in the world who don't want to be slaughtered, plundered and enslaved by them are their enemies. This fully shows the degree of civilization in Mongolia at that time-that is, close to animals. Declare that "the land covered by blue sky should become Mongolian pasture."