Tao Te Ching: Chapter 8
Who thinks his great achievements poor Shall find his vigour long endure. Of greatest fulness, deemed a void, Exhaustion ne'er shall stem the tide. Do thou what's straight still crooked deem; Thy greatest art still stupid seem, And eloquence a stammering scream.
Constant action overcomes cold; being still overcomes heat. Purity and stillness give the correct law to all under heaven.