Chastise the good and he will mend, chastise the bad and he will grow worse.
More Italian Proverbs:
He who guesses well prophesies well.Italian
When ill luck falls asleep, let none wake her.
Italian
What has not been, may be.
Italian
The good seaman is known in bad weather.
Italian
It is better to hear the nightingale sing than the mouse gnaw.
Italian
Love rules his kingdom without a sword.
Italian