There will be trouble if the cobbler starts making pies.
More Russian Proverbs:
Curious Varvara's nose was torn off.Russian
One never tires working for oneself.
Russian
An old dog can't get used to chains.
Russian
Absentmindedness is searching for the horse you are riding.
Russian
Meanness looks through one eye only, ambition is blind.
Russian
It's a crime if you get caught.
Russian