One day in the sky is worth ten years on earth; one day on earth is worth ten years underground. People in the sky are carefree and enjoy their time; people in the mortal world are ordinary, suffering from birth, old age, illness and death; people in the underground are suffering and suffering, and their days are like years. How can all living beings be equal? Pangu created heaven and earth, and Nuwa created man and created the world. From then on, there were three realms of heaven, earth and man. The Buddha said that all living beings are equal, but the weakest among the three realms are humans, and the most ignorant are also humans. Those who have the real power and real emotions to change everything in the world are actually humans.