The corn that is taken to a bad mill. will be badly ground.
More Danish Proverbs:
Let another man praise thee, not thine own mouth.Danish
He who has many irons in the fire, will let some of them burn.
Danish
Tell nothing to thy friend which why enemy may not know.
Danish
A thankless man never does a thankful deed.
Danish
Vice is most dangerous when it puts on the garb of virtue.
Danish
It is not for nothing that the devil lays himself down in the ditch.
Danish