Rotten straw can harm a healthy horse.
More Russian Proverbs:
Tell me who's your friend and I'll tell you who you are.Russian
The hearth in our house is warmer than our neighbor's.
Russian
Your body belongs to the Tsar, your soul to God, and your back to the squire.
Russian
Death is not found behind mountains but right behind our shoulders.
Russian
The thief makes perhaps one mistake; those he stole from made a hundred.
Russian
The horses of hope gallop, but the asses of experience go slowly.
Russian