The cats that drive away mice are as food as those that catch them.
More German Proverbs:
One man is another's devil.German
Tired oxen must tread hard.
German
Time is the herald of truth.
German
Where God bestows an office, he provides brains to fill it.
German
They must hunger in frost who spring-time have lost.
German
At court there are many hands, but few hearts.
German