Faber is cautious. He shows this trait when...
1. Montag calls him to enlist his help. Montag asks how many copies of the Bible are still out there. Faber says
"This is some sort of trap. I can't talk to just anyone on the phone." (pg 76)
2. When Montag does go to his home, Faber is reluctant to let him in. Faber describes himself as a coward who could have spoken out but was too cautious and kept himself safe. He tells Montag.
"I saw the way things were going, a long time back. I said nothing. I'm one of the innocents who could have spoken up and out when no one would listen to the 'guilty,but I did not speak and thus became guilty myself." (pg 82)
3. When Montag is going back to consult Beatty at the firehouse, Faber gives him the earpiece he developed. Why didn't he use it before?
"Well I played the market and built all of this and I've waited. I've waited trembling, half a lifetime for someone to speak to me. I dared speak to no one.....I've had this item for months. But I almost let you go. I am that afraid." (pg 90)
The green earpiece allows Faber to talk to Montag and hear what is being said to him. It allows Faber to protect himself.
"I can sit comfortably home, warming my frightened bones, and hear and analyze the firemen's world, find its weaknesses, without danger. I'm the Queen Bee, safe in the hive. You will be the drone, the traveling ear.......See how safe I play it, how contemptible I am?" (pg 90-100)
3. When Montag is running, and the government has brought in a new Hound, Montag runs to Faber's house.
"Then Faber moved and put out his hand and grabbed Montag and moved him in and sat him down and went back and stood in the door, listening. The sirens were wailing off in the morning distance." (pg 130)
Faber, having almost been identified by the green earpiece, has decided to move to St. Louis. But even as they watch the new Hound arrive on TV, he notices what Montag has touched and where he is sitting.
"Montag saw the look. They both looked quickly about the house and Montag felt his nostrils dilate and he knew that he was trying to track himself and his nose was suddenly good enough to sense the path he had made in the air of the room and the sweat of his hand hung from the doorknob......He saw Faber stop his own breath for fear of drawing that ghost into his own body, perhaps, being contaminated with the phantom exhalations and odors of a running man." (pg 133)
Montag leaves Faber with things to do to avoid the Hound. Faber says he will take care of it. He will head to St. Louis, and he tells Montag that he can contact him at General Delivery, St. Louis. He won't even give him a definite address. He has more courage now, but he is still cautious.
These quotes are from my edition of the book. However they should be in close proximity to the pages given.