In Canto XXX of The Divine Comedy, Dante and Virgil have survived the depths of hell and ascend to the Mountain of Purgatory which is on a displaced rock that resulted from Satan’s fall creating Hell.  The mountain’s seven terraces correspond to the seven deadly sins.  The sin here is classified here as based on psychological motives.

Love frames the Mountain of Purgatory.  That which flows from God is pure. That which flows through man can become twisted.  Allegorically, Purgatorio represents Christian life.

You may read Canto XXX of Dante’s The Divine Comedy here:

http://www.bartleby.com/20/230.html

Alternatively, you may listen to this classic in its audiobook format here: