The valley's horrible stench is coming from more burning tombs.
Dante and Virgil retreat until they’re behind one of the tombs.
Dante reads the inscription on the tomb. It says, "I hold Pope Anastasius." This was a pope who denied the divinity of Christ.
Virgil, who apparently has a really sensitive nose, tells Dante that they’re going to sit tight here until their delicate sinuses get used to the horrible smell.
Dante says they should use this time wisely. The irritable Virgil tells him to shut up, because he’s already thought of that.
Virgil begins explaining the structure of Hell to Dante. We know—we could’ve used this lesson earlier, too.
Virgil starts with the next circle. That would be the seventh, the circle of the Violent. It’s divided into three smaller rings, to indicate the three types of violence: 1) violence against God and nature, 2) violence against oneself, and 3) violence against one’s neighbor.
Those who practice violence against their neighbors—like murderers, plunderers, and robbers—reside in the first sub-circle.
Suicidal people inhabit the second ring.
Blasphemers and usurers occupy the third ring.
But the most evil category of sin, Virgil explains, is fraud. And sadly, this sin is most particular to human beings.
So, in the eighth circle reside the sinners whose fraud "cut[s] off / the bond of love that nature forges." These include people like hypocrites, flatterers, sorcerers, falsifiers, simonists, thieves, barrators, and panderers, to name just a few.
But, that’s just ordinary fraud. The ninth circle contains those sinners who’ve committed really bad or treacherous fraud.
Dante says to master Virgil that he understands. But what about all those in the previous circles? Why aren’t the sinners there punished as harshly as those in the circles to come? Isn’t God angry with them too?
Virgil scolds him for being so stupid. Seriously. He reminds him of a beloved book, Aristotle’s Ethics, which divides sin into three categories: "incontinence, malice, and mad bestiality." (By "malice," he means fraud, "incontinence" means lack of self-control, and by "mad bestiality," he means violence.)
The least offensive of these three is incontinence and that’s what all the prior circles have contained (lust, gluttony, avarice, prodigality, wrath, sullenness—if you’re keeping track).
Dante, being a model student, now asks Virgil to revisit the sin of usury (yes, we missed the first mention too) and why it’s so bad. Usury is the practice of charging exorbitant interest rates on loaned money.
So Virgil starts in with all this mystic stuff about how man’s labor and art follow nature and thus are in line with God’s will. In other words, it is good and natural for men to labor and to earn their living off the sweat from their brows.
Usurers, in making a living by generating money unnaturally, violate nature and thereby sin.
Lesson over. Virgil notices that the constellations in the sky are changing. So it’s time to move on.