It’s a poor sheep that cannot carry its own wool.
More German Proverbs:
The master's eye does more than both his hands.German
The empty waggon must make room for the full one.
German
Hunger is the best cook, but he has nothing to eat.
German
Revenge does not long remain unrevenged.
German
Never give advice unasked.
German
Asses sing badly, because they pitch their voices too high.
German