He who can, does. He who cannot, teaches
The saying that an ounce of action is better than bushels of teaching, or that ‘example is better than precept, has been differently quoted in the given statement. Those who are full of precepts are inactive people. They cannot express their teachings or ideas into actions. Life is sustained by action. Indeed, life means activity. Recipe, howsoever nice, cannot feed us, a mere prescription cannot effect cure. The dish must be cooked before it can feed us. Similarly, in the other sense, a medicine must be prepared to cure a patient. This well illustrates the relative importance of passive teaching and active doing.