How does Pilgrim's Progress illustrate the most important aspect of Puritanism?

The words of scripture are as powerful when verbalized as they are when read, and the characters often quote scripture to one another. They also speak aloud to comfort themselves and one another, as when Christian is in the Valley of the Shadow of Death (77). Moreover, the pilgrims spend a great deal of time of their pilgrimage in conversation, and Bunyan uses these dialogues as an opportunity to communicate theology to his readers. The written word as scripture was the crux of Puritanism, and accordingly, the word is an exceptionally important motif in this seminal Puritan text.