A Famous Proverb

He who knows not and knows not that he knows not is a fool, shun him.

He who knows not and knows that he knows not is a child, teach him.

He who knows and knows not that he knows is asleep, wake him.

And he who knows and knows that he knows is wise, follow him.

(I will add one extra line...
He who knows, but keeps it to himself is a genius, ask him.)