According to the Divine Comedy, Dante and Virgil first descend through the back of Lucifer and then climb up his rump to exit from hell. That way they go through the Earth’s centre and reverse their route, so that, from that moment, instead of descending, they commence to ascend.
The new process of purification-transformation they begin now, corresponds with Purgatory. Thus, the poet jubilantly exclaims that after leaving behind such a cruel sea (the Inferno), he will now set sail to navigate in calmer waters.
And of that second region will I sing,
In which the human spirit from sinful blot
Is purg'd, and for ascent to Heaven prepares.
(Purgatory, Canto I)
Nevertheless, before reaching Purgatories’ gate, Dante and Virgil must cover an intermediate section: the “Antepurgatory”, where they come in contact with the negligent, those who, for one reason or another, died without making good use of the spiritual opportunities offered to them, plus those who, having lived in sin, repented themselves before dying.
In this phase, Dante moves away more and more from the material world’s influence, while becoming aware of his spiritual consciousness.
Before Dante and Virgil appears a “heavenly ferryman”, it´s an angel transporting a group of souls which he leaves by the beach. The souls ask the two travellers to point them the way to the mountain (the way to the spiritual summits), an indication the travellers are unable to provide.
Nevertheless, at the beginning of Purgatories third song, Dante and Virgil stand by a mountain, whose steep rocks seem inaccessible to them.
Dante then exclaims: “Master of mine, which path shall we take?” to which Virgil responds: “Do not take any step backwards; keep following me to the mountains’ summit, until we find some expert guide”
A most appropriate counsel since, once the candidate has firmly decided to set foot on the path leading to the mountain of the spirit, he can`t afford to fall prey to any type of discouragement. There is really only one option, the only possibility is to continue the journey with determination, as we must keep present that Purgatory represents a second phase of the soul’s purification.
At the beginning of canto IX, he leaves a record of a vision he had while in a dream state: an eagle with golden feathers, hovering in the sky, suddenly, dives like a thunderbolt and carries him to the fire’s sphere (the Sun), where both of them seem to be ablaze.
Then in a vision did I seem to view
A golden-feather'd eagle in the sky,
With open wings, and hov'ring for descent,
Therewith, it seem'd,
A little wheeling in his airy tour
Terrible as the lightning rush'd he down,
And snatch'd me upward even to the fire.
There both, I thought, the eagle and myself
Did burn; and so intense th' imagin'd flames,
That needs my sleep was broken off.
(Purgatory, Canto IX)
We have here a clear indication relative to the Holy Spirit’s touch.
Purgatory, as described by Dante in the Divine Comedy, consists of a mountain with seven terraces, each of them related to one of the capital sins. Before crossing Purgatory’s gate, the angel at the doorway engraves in the front, of all those arriving there, as many “P” letters as capital sins they have committed.
The letter, that denotes the inward stain,
He on my forehead with the blunted point
Of his drawn sword inscrib'd. And "Look," he cried,
"When enter'd, that thou wash these scars away."
(Purgatory, Canto IX)
In so far as each sin is expiated, a “P” is erased from the candidates’ front so that he can climb to a higher terrace to purge up his next transgression.
The first terrace is for the prideful who are forced to walk while carrying heavy stones on their backs. The second one is assigned to the envious. The wrathful are punished in the third terrace. In the fourth terrace the slothful have to run all the time in order to expiate their sin. The fifth terrace is where the greedy are punished. The gluttons are assigned to the sixth terrace where no food or beverage is provided, except for a cascade of icy water. The seventh terrace is reserved to the lusty where they are consumed in a wall of fire until they’re cleansed from their sin.
Thus, Dante is compelled to go through the seven stepped circles of Purgatory, where he comes across a whole series of characters, representative of the seven capital sins their souls have to be purified of.
At the mountain’s summit sits the Garden of Eden, where the souls exist in a state of innocence and prepare themselves spiritually to ascend to Paradise.
Once Dante has become worthy of entering Paradise, he meets again with Beatrice (the “Other”, the Spirit-Soul).
That way, the candidate is permitted to access the third phase that he must traverse (“the Rubedo”), a stage of the alchemical process usually named “the alchemical weddings of soul and Spirit”, whose goal is forming up the “Rebis”, the male-female being, the edenic or platonic primordial mystical unity. Such mystical union or alchemical wedding, represented by the encounter of Dante and Beatrice at Eden, is the evidence that the candidate has overcome all the obstacles that separated him from his inner God.
Thus, after finally having become worthy of Beatrice, she says to Dante:
"Ope thou thine eyes, and mark me: thou hast seen
Things, that empower thee to sustain my smile."
(Paradise, Canto XXIII)
Such words express much more than a simple love metaphor, since only those successful in completing the long path to the Spirit Soul, are capable of “opening the eyes” and are able to sustain “the smile” of the Spirit, which in plain language implies to the inner Being see face-to-face, bear the sight of the Spirit’s Fire and understand the universal and metaphysical truths transcending our own world.