The mind is the Buddha. Buddha and common people, enlightenment and delusion have different names, but they have the same origin. You’ve got to study your minds first! Human nature in itself is neither good nor bad. Sages and common people have the same complete nature. There isn’t some special way to apply this theory to reality. Your own mind reflects the entire world. Flowing water doesn’t have some beginning or ending, nor the changing moon, nor the moon’s reflection on the water. If you understand this, you have all that is necessary.