Purgatory are scenes illustrative of humility. While looking on these
scenes, which seem to live and speak in their beautiful and compelling
reality, the poet turns and sees approaching the forms of the proud. On
earth they had exalted themselves as if they had the weight of the world
on their shoulders, so now they are seen bent under huge burdens of
stone, crumpled up in postures of agonizing discomfort. The poet, to let
us know that he shares in their punishment, says:

"With equal pace as oxen in the yoke,
I, with that laden spirit, journey'd on
Long as the mild instructor suffer'd me."
(Purg. XII, 1)

He apostrophizes them, but the words are really an upbraiding of himself
for pride.

"O ye proud Christians, wretched weary ones,
Who in the vision of the mind infirm,
Confidence have in your backsliding steps,
Do ye not comprehend that we are worms
Born to bring forth the angelic butterfly
That flieth unto judgment without screen?
Who floats aloft your spirit high in air?
Like are ye unto insects undeveloped
Even as the worm in whom formation fails!
As to sustain a ceiling or a roof
In place of corbel, sometimes a figure
Is seen to join unto its knees its breast
Which makes of the unreal, real anguish
Arise in him who sees it: fashioned thus