<em>"So it was the hand that started it all... his hands had been infected, and soon it would be his arms...his hands were ravenous". </em>(Fahrenheit 451 by Ray Bradbury, page 41).
This quote explains a part of the story in which Montag returns back to his home after another book-burning mission. But this one ended tragically because a woman set her house on fire. Before the woman commands herself on this decision, Montag takes a specific book with him. And is after he reads this book, that he starts his rebellion against the state. So that's why the book says that it would this hand (Montag's hand) that started it all.
