Greatest virtue

"The greatest perfection seems imperfect, But its work undecaying remaineth. The greatest fulness is emptiness-checked, But its work 's not exhausted nor waneth. The straightest line resembleth a curve; The greatest sage as apprentice will serve ; Most eloquent speakers will stammer and swerve. Motion conquers cold. Quietude conquers heat Purity and clearness are the world's standard."