Dropping knowledge is the hardest thing for the mind.
Knowledge is that which is in your mind or intellect but you have no experience of. It is only utilitarian. You can live without it. It is great for argument but not essential for moment to moment living.
Knowing is that which is an intrinsic aspect of your Be-ing. You live as you know. Knowing and Being are the same. They are inseparable. For example, a boy has a knowledge that a bike can be ridden because he can see another boy riding.
But until he learns how to ride and really rides the bike, his knowledge will never help him. As soon as he learns to ride,his knowledge now becomes knowing, since he relates with the bike in a different way.
It is even wrong to say knowledge becomes knowing! What happens is that knowledge drops and knowing arises. In fact, for knowing to happen, knowledge must drop. Dropping knowledge is the hardest thing for the mind. Think about it