Beware of a quiet dog and still water.
More Russian Proverbs:
The elbow is near, but try and bite it.Russian
After a storm fair weather, after sorrow joy.
Russian
A ruler without a nation is like a flower without the sun.
Russian
A liar can go round the world but cannot come back.
Russian
Cry and the whole world cries with you.
Russian
There is plenty of sound in an empty barrel.
Russian