The wise do as much as they should, not as much as they can.
More French Proverbs:
Great wits meet.French
Some think they have done when they are only beginning.
French
Were the devil to come from hell to fight, there would forthwith be a Frenchman to accept the challenge.
French
According to the arm be the bleeding.
French
Anger is a bad counsellor.
French
If the young only knew; if the old only could.
French