The essence of teh is comparable to the state of a young boy. Poisonous insects will not sting him, wild beasts will not seize him, birds of prey will not attack him. The bones are weak, the muscles are tender, it is true, but his grasp is firm.
He does not yet know the relation of the sexes, but he has perfect organs, nevertheless. His spirit is virile, indeed! He can sob and cry all day without becoming hoarse, his harmony (as a child) is perfect indeed!
To recognize this harmony (for growth) is to know the eternal'. To recognize the eternal is to know enlightenment. To increase life (to cause things to grow) is to know blessedness. To be conscious of an inner fecundity is strength. Things fully grown are about to decay, they are the opposite of Tao. The opposite of Tao soon ceases.