--- Matthew Treherne, in the BBC In Our Time
program on Purgatory, discussing Dante's Purgatorio, at time code 21:07:
Matthew Treherne: Dante divides the mountain into seven terraces, each of which corresponds to a particular vice.
Melvyn Bragg: Are they the seven deadly sins?
Treherne: Yes. Dante would think of these as vices, which are habits to be corrected, rather than sins to be punished - that's a really important distinction to what happens in Hell.
According to Wikipedia, "The Roman Catholic Church distinguishes between vice, which is a habit of sin, and the sin itself, which is an individual morally wrong act. ... It is the sin, and not the vice, that deprives one of God's sanctifying grace and renders one deserving of God's punishment. Thomas Aquinas taught that "absolutely speaking, the sin surpasses the vice in wickedness". On the other hand, even after a person's sins have been forgiven, the underlying habit (the vice) may remain."