Quiet water wears down a mountain.
More Serbo-Croatian Proverbs:
One who gets up early is doubly lucky.Serbo-Croatian
The early bird catches the first worm.
Serbo-Croatian
Cute lamb sucks two ewes.
Serbo-Croatian
Iron is worked when it's still hot.
Serbo-Croatian
A sparrow in the hand is better then a pigeon on the branch.
Serbo-Croatian
First leap, and then say "hop".
Serbo-Croatian