The first line of the novel is full of violence.
IT was a special pleasure to see things eaten, to see things blackened and changed. With the brass nozzle in his fists, with this great python spitting its venomous kerosene upon the world, the blood pounded in his head, and his hands were the hands of some amazing conductor playing all the symphonies of blazing and burning to bring down the tatters and charcoal ruins of history.
This opening line describes the violent images associated with firemen burning books and erasing knowledge from history. The images are described poetically, glorifying the violence. The narrator illustrates the way (most) firemen view their jobs in Montag's world: the destruction is compared to playing a symphony, a poetic view of violence. This is the point. Violence is sanctioned by this society. Books are burned and people who read them are hunted down, all in the name of the so-called social good.
Through the course of the novel, Montag reverses his opinion and goes from enjoying his job to hating it. The descriptions of violence shift with Montag's shift in perspective. By the end, violence becomes (in Montag's eyes) a terrible, destructive force.
Montag is really not out for revenge. When he becomes interested in books and knowledge, his reason for doing so is a desire for knowledge. That being said, he does exact revenge on Beatty. Montag says, "We never burned right." He then turns the flames on Beatty. This is a vengeful moment. But for the most part, Montag is more interested in knowledge than in revenge.