Quote 28
[Virgil]: "How many up above now count themselves
great kings, who’ll wallow here like pigs in slime,
leaving behind foul memories of their crimes!" (Inf. VIII, 49-51)
In the mud of the Fifth Circle, Virgil points out how different the standards of fame are in the afterlife. His message seems to be that those who garner the most fame and prestige in the mortal world do so by wicked means and thus will have no such stature in Hell, but will be reduced to a position of low bestiality, like "pigs in slime."
Quote 29
[Virgil]: "Now you must cast aside your laziness,"
my master said, "for he who rests on down
or under covers cannot come to fame;
and he who spends his life without renown
leaves such a vestige of himself on earth
as smoke bequeaths to air or foam to water." (Inf. XXIV, 46-51)
Virgil implies that fame must be won through hard labor. Only through honest work can one leave his mark on the world. Those afflicted with laziness may never gain fame and thus take the risk of being forgotten by the mortal world, just as "smoke on air" or "foam [on] water" remain visible for but a few moments before fading away.
Quote 30
[Virgil]: Therefore, I charge you, if you ever hear
a different tale of my town’s origin,
do not let any falsehood gull the truth."
And I: "Oh master, that which you have spoken
convinces me and so compels my trust
that others’ words would only be spent coals." (Inf. XX, 97-102)
In relating the story of Mantua’s true origins, Virgil attempts to cast off his reputation as a deceitful magician and stake his reputation on the truth of his words.