Those who are ailing do not know these things. Indeed, they do not even understand that they are sick. And who then can ever persuade with argument people thus inclined that they are under the sway of sickness and disease? They imagine rather that it is health to accomplish the wishes of the flesh, and to practise all its lust and desire. And, just as no one will ever make those who are gone mad and deranged take account of the fact that they are insane, just so neither will anyone persuade those who are wallowing in the passions, and ruled by them, and unconscious of their being possessed, that they are in a bad way, and so make them change for the better. For they are blind, and neither do they believe that anyone else can see. Thus they live, deprived of sight and unconvinced they can lift up their eyes.
(Saint Symeon the New Theologian)