When the great Tao is forgotten, goodness and piety appear. When the body's intelligence declines, cleverness and knowledge step forth. When there is no peace in the family, filial piety begins. When the country falls into chaos, patriotism is born.
So sometimes things are ahead and sometimes they are behind; Sometimes breathing is hard, sometimes it comes easily; Sometimes there is strength and sometimes weakness; Sometimes one is up and sometimes down. Therefore the sage avoids extremes, excesses, and complacency.
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.
The cords of passion and desire weave a binding net around you. Worldly confrontation makes you stiff and inflexible. The trap of duality is tenacious. Bound, rigid, and trapped, you cannot experience liberation.
Seal the openings, shut the doors, and until your last day you will not be exhausted. Widen the openings, interfere, and until your last day you will not be safe.