Cassius tells Brutus that many men wish that "noble Brutus had eyes in his head." What does Cassius insist that Brutus cannot see?

I think this is in Act one sc. 2 when Cassius tries to flatter Brutus into joining the conspirators. He tells Brutus that he can not see his own worthiness that is so evident to all who look upon him,

"And it is very much lamented, Brutus,

That you have no such mirrors as will turn

Your hidden worthiness into your eye

That you might see your shadow."