As the ego becomes strong it starts surrounding intelligence like a thick layer of darkness. Intelligence is light, ego is darkness. Intelligence is very delicate, ego is very hard. Intelligence is like a roseflower, ego is like a rock. And if you want to survive, they say - the so-called knowers - then you have to become rock-like, you have to be strong, invulnerable. You have to become a citadel, a closed citadel, so you cannot be attacked from outside. You have to become impenetrable.