Devine Comedy.

Devine comedy is a poem written by Dante Alighieri it is widely considered as the greatest work of Italian and even world literature.
The poem literally tells of Dante's travel through hell, purgatory and heaven but the underlaying meaning is the souls journey to god.
The poem is spilt into

1. Inferno (hell)
2. Purgatorio (Inbetween)
3. Paradiso (heaven)

The 7 deadly sins come from Purgatorio, directly translated as purgatory.
This is a place inbetween heaven and hell of suffering where souls will be cleansed of sin before going to heaven.