In the book, Montag wants to undermine society. His only idea is to plan books in the homes of firefighters to make them look bad. He goes to Faber for help but Faber does not want to help him.
What Montag does is not really something that convinces Faber. It is more like Montag blackmails him. What Montag does is to start tearing up a Bible. As far as Faber knew, there were none around and he really wanted to read it. So when Montag starts tearing it up, Faber tells him to stop -- that if he stops, Faber will help him.
Montag’s plan was to print copies of books which, with the help of Faber’s connections, would plant them in firemen’s houses after which they would sound the alarm as signal for the houses to be burnt. According to Faber, this would be the most effective way to destroy the structure of the fireman unit because it would raise distrust amongst the professionals charged with the responsibility to destroy books. However, due to his self-confessed fear, Faber did not want to take part in such a plan as it would lead to his demise. Moreover, he thought Montag’s plan was not as easy to implement as it sounded and wanted nothing to do with it. Montag therefore arm twisted Faber into cooperation by tearing off a few pages from the bible and threatening to destroy the entire book, something that Faber would not allow knowing how precious it was as one of the last copies to exist.
He would destroy the book page by page until Faber cooperated