This question refers to the book Fahrenheit 451. In this book, we learn that Montag was meant to burn books, as this is what firefighters do in this society. However, he rebels and begins to enjoy them.
Faber gave Montag harsh warnings about his behaviour, warning him that he should keep his books a secret. However, when some women come to visit Montag's wife, he cannot resist the temptation and ends up reading some poetry to them. The result of this is that his wife finds out about his secret, and she is the one who eventually calls the firefighters to burn their own house down.