In the second circle of the Sun in Dante’s Paradiso, the main voice is the Light of St. Bonaventure (c.1217-1274) – a professor at the University of Paris, and a leader of the Franciscan Order.
In Bonaventure’s main work “The Soul’s Journey into God” we can see several aspects which Dante is using in the Paradiso, f.ex. a description of the final moments of the ascent:
“For no one is in any way disposed for divine contemplation that leads to mystical ecstasy, [..] such desires are enkindled in us in two ways: by an outcry of prayer [..] and by the flash of insight by which the mind turns most directly and intently towards the rays of Light.”
The idea of Dante’s Purgatory as purification and preparation for Divine knowledge is also described by Bonaventure, when he warms how the reflections of the Divine in the material world:
“is of little or no value
unless the mirror of our soul
has been cleaned and polished.
Therefore, man of the Divine,
first exercise yourself in remorse of conscience
before you raise your eyes
to the rays of Wisdom reflected in its mirrors,
lest perhaps from gazing upon these rays
you fall into a deeper pit of darkness.”
Which also ties into Dante’s warning in Canto 2 of Paradise, that the Journey could be risky if one is not yet fully prepared!
A great advice from Bonaventure at the end of the Preface is the following:
you should not run rapidly
over the development of these considerations,
but should mull them over slowly
with the greatest care.