Clay is molded to form a cup, But it is on its non-being that the utility of the cup depends. Doors and windows are cut out to make a room, But it is on its non-being that the utility of the room depends. Therefore turn being into advantage, and turn non-being into utility.
Peacefulness is an inner sense of calm - it comes from becoming still - in order to reflect and meditate on our inner wisdom and receive answers. A peaceful heart is one that is free from worry and rouble. It's becoming quiet so we can look at things quietly so we can more clearly understand them and thus come up with creative solutions. It is learning to live in the present. Freedom from desire leads to inner peace.
If you close your mind in judgements and traffic with desires, your heart will be troubled. If you keep your mind from judging and aren't led by the senses, your heart will find peace.
Thirty spokes meet in the hub. Where a wheel isn't is where it's useful. Hollowed out, clay makes a pot. Where the pots not is where it's useful. Cut doors and windows to make a room. Where the room isn't, there's room for you. So the profit in what is, is in the use of what isn't.