Lao Tzu 《Tao Te Ching》 27.Perfection

The perfect traveller leaves no trail to be followed;
The perfect speaker leaves no question to be answered;
The perfect accountant leaves no working to be completed;
The perfect container leaves no lock to be closed;
The perfect knot leaves no end to be ravelled.

So the sage nurtures all men
And abandons no one.
He accepts everything
And rejects nothing.
He attends to the smallest details.

So the strong must guide the weak,
For the weak are raw material to the strong.
If the guide is not respected,
Or the material is not cared for,
Confusion will result, no matter how clever one is.

This is the secret of perfection:
When raw wood is carved, it becomes a tool;
When a man is employed, he becomes a tool;
The perfect carpenter leaves no wood to be carved.