An enemy does not sleep.
More French Proverbs:
A mad dog cannot live long.French
He that has not money in his purse should have honey in his mouth.
French
One fool always finds a greater fool to admire him.
French
It would be a very big book that contained all the maybes uttered in a day.
French
An army marches on its stomach.
French
A sin that is hidden is half forgiven.
French