This is from the beginning of the book when Guy montage first meet Clarisse and they develop a friendship and we start to get an understanding of what its like in the United States.
This is when Montag and the rest of the crew are called to a house to burn it. Once they were done pouring kerosene they told the lady to exit the house but instead, she took out a match and lit her house on fire.
And wasn't it this bright boy you selected for beatings and tortures after hours? Of course it was. We must all be alike. Not everyone born free and equal, as the Constitution says, but everyone made equal. Each man the image of every other; then all are happy, for there are no mountains to make them cower, to judge themselves against. So! A book is a loaded gun in the house next door. Burn it. Take the shot from the weapon. Breach man's mind. Who knows who might be the target of the well-read man?