One of my favourite is Bruce Lee. He said, "Knowing is not enough, we must apply, willing is not enough, we must do." I really like his philosophy. Whether it is for martial arts or otherwise, we can apply it in our daily activity.
To know without applying is like a soul without body, like a manager without his subordinates. At school we learn knowledge from books but were we able to apply what we have learnt? Knowledge is not useful when they are not applied. Much akin to the situation that there are job seekers but no vacancy.