As the Tathagata said in the Monkey King.

Tathagata smiled and said, "You are so powerful that you can only read Sundays, but you can't know everything about Sundays, and you can't know all kinds of Sundays." The Bodhisattva asked about the kind of Sunday, and the Tathagata said, "There are five immortals on Sunday, who are the gods and ghosts of heaven and earth; There are five kinds of insects, namely Mao Yukun. This fellow is not heaven, earth, god, man, ghost, scale, hair, feather or Kun. There are four monkeys in the world, which do not belong to ten categories. " "Who are those four monkeys?" The bodhisattva asked. For example, "The first one is Ling Ming boulder, who knows the changes, weather, location and stars. The second is the red horse monkey, who knows yin and yang, knows people, is good at going in and out, and avoids death and prolongs life. The third is the armless ape, taking the sun and the moon, shrinking the mountain of money, distinguishing the blame, and being silent. The fourth is Liu Er's macaque, who is good at listening and understanding. These four monkeys do not belong to ten categories, nor can they reach the name of two rooms. I think Wukong is a monkey named Liu Er. If this monkey stands in one place, it can know things thousands of miles away, and so can ordinary people. Therefore, I am good at listening, observing reason, and knowing the past and the future. Liu Er's macaque is also a homonym of the real Wukong. " Macaques smell Tathagata and tell the truth. He was so scared that he jumped up and left.