He who can does, he who cannot, teaches.
More German Proverbs:
Happiness opens the arms and closes the eyes.German
One crow does not make a winter.
German
He who has once burnt his mouth always blows his soup.
German
To every one his own is not too much.
German
Monks, mice, rats, vermin, seldom sunder without harming.
German
There's no rest for the wicked.
German