Sorrow and happiness are the heresies of virtue; joy and anger lead astray from TAO; love and hate cause loss of virtue. The heart unconscious of sorrow and happiness - that is perfect virtue. One, without change - that is perfect repose. Without any obstruction - that is the perfection of the unconditioned. Holding no relations with the external world, - that is perfection of the negative state. Without blemish of any kind, - that is the perfection of purity.
ZhuangziThe mind remains undetermined in the great Void. Here the highest knowledge is unbounded. That which gives things their thusness cannot be delimited by things. So when we speak of 'limits', we remain confined to limited things. The limit of the unlimited is called 'fullness.' The limitlessness of the limited is called 'emptiness.' Tao is the source of both. But it is itself neither fullness nor emptiness
ZhuangziWe possess our body by chance and we are already pleased with it. If our physical bodies went through ten thousand transformations without end, how incomparable would this joy be! Therefore the sage roams freely in the realm in which nothing can escape, but all endures.
ZhuangziIf a man is crossing the river and an empty boat collides with his skiff, even though he is a bad tempered man he will not become very angry. But if he sees a man in the other boat he will scream and shout and curse at the man to steer clear. If you can empty your own boat crossing the river of the world, no one will oppose you, no one will seek to harm you. Thus is the perfect man - his boat is empty.
Zhuangzi