Definition of Allegory
Pilgrim's Progress is a work of religious allegorical fiction, meaning that the novel has two levels of meaning at all times—the level of the character Christian's journey from the City of Destruction to the Celestial City (or, in Part 2, Christiana's identical journey), and the deeper, spiritual level depicting an average Christian's journey to leave sin behind and reach eternal life with God in Heaven. Broadly speaking, Bunyan uses allegory to give contemporary readers an engaging, accessible picture of what a Christian's journey to Heaven is like. Christian and Christiana, then, are stand-ins for "everyman"—or "every-Christian," as the case may be.
While rushing to enter the Wicket-gate on Evangelist's urging, Christian (initially joined by Pliable) accidentally plunges into a miry bog called the Slough of Despond. The visual imagery of a squelchy, muddy struggle conveys the desperation that a Christian, newly persuaded of their sinful state, often faces:
Unlock with LitCharts A+Now I saw in my Dream, that [...] they drew near to a very miry Slough, that was in the midst of the plain and they, being heedless, did both fall suddenly into the bog. The name of the slough was Dispond. Here therefore they wallowed for a time, being grievously bedaubed with the dirt; and Christian, because of the Burden that was on his back, began to sink in the mire.
Soon after embarking on his pilgrimage, heading to the Wicket-gate at Evangelist's urging, Christian meets a man named Mr. Worldly Wiseman, who tells Christian to get his Burden removed by easier means—namely, by visiting a fellow named Legality. Worldly Wiseman's advice proves disastrous, however—en route, Christian becomes convinced that an overhanging mountain is going to fall and crush him—and an allusion to the biblical book of Galatians explains why. As Evangelist puts it,
Unlock with LitCharts A+He to whom thou was sent for ease, being by name Legality, is the Son of the Bond-woman which now is, and is in bondage with her children; and is in a mystery this Mount Sinai, which thou hast feared will fall on thy head.
Recounting his pilgrimage to Christian, Faithful describes his violent encounter with a figure called Adam the First. The episode is an allegory that Bunyan uses to dramatize the relationship between the Law and the Gospel in Christian belief:
Unlock with LitCharts A+[...] with that he struck me another deadly blow on the breast, and beat me down backward, so I lay at his foot as dead as before. So when I came to myself again I cried him mercy; but he said, I know not how to shew mercy; and with that knocked me down again. He had doubtless made an end of me, but that one came by, and bid him forbear.
During the final stage of their journey to the Celestial City, when Christian and Hopeful begin to cross over the River of Death, Christian, sinking, alludes to a Psalm:
Unlock with LitCharts A+They then addressed themselves to the Water; and entring, Christian began to sink, and crying out to his good friend Hopeful, he said, I sink in deep Waters; the Billows go over my head, all his Waves go over me[.]